Information storage medium, recording method, and recording apparatus

ABSTRACT

According to one embodiment, an information storage medium in which layer  0  and layer  1  are arranged from a read surface, a system lead-in area, data lead-in area, data area, and middle area are arranged from an inner circumference of the layer  0,  and a system lead-out area, data lead-out area, data area, and middle area are arranged from an inner circumference of the layer  1.  A guard track zone is arranged on a side of the data area in the data lead-out area, and a reference code zone, R physical format information zone, recording management zone, and drive test zone are arranged in the data lead-in area of the layer  0  and padding of the guard track zone of the data lead-out area is performed after padding of the drive test zone of data lead-in area and recording of the recording management zone.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.11/668,835, filed Jan. 30, 2007 and claims the benefit of priority fromJapanese Patent Applications No. 2006-023924, filed Jan. 31, 2006; andNo. 2006-126241, filed Apr. 28, 2006, the entire contents of each ofwhich are incorporated herein by reference.

BACKGROUND

1. Field

One embodiment of the invention relates to an information storage mediumsuch as a recordable optical disc, a recording method, and a recordingapparatus.

2. Description of the Related Art

In recent years, a digital versatile disc (DVD) has been practicallyused as a large-capacity optical disc. As a recordable DVD, a recordableDVD-R, a rewritable DVD-RW, and a DVD-RAM have been standardized. Onceinformation is recorded on a recordable disc DVD-R, a recorded areacannot be rewritten. A conventional recordable DVD-R includes a powercalibration area (PCA), a recording management area (RMA), and a datarecording area (DA) in which an actual recording process is executedfrom the inner circumference side (for example, see Jpn. Pat. Appln.KOKAI Publication No. 2002-245625 (paragraphs 0041 to 0052, FIG. 1)).

Furthermore, the data recording area DA includes a lead-in area in whichrecording parameter information and the like to be read when recordingdata is reproduced from a data area, a data area in which the recordingdata is recorded, and a lead-out area in which end information or thelike to be read when reproducing of the recording data recorded in thedata area is ended is recorded. The lead-in area is an area in whichrecording parameter information or the like is recorded before data isrecorded in the data area. The lead-out area is an area in which endinformation is recorded before recording of recording data on an entireDVD is completed. The capacity of each area is predetermined andunchangeable.

When information is recorded on such a DVD (recording is performed fromthe inner circumference side of the data area), test recording isperformed in the PCA area first. In this test recording, because thecharacteristics of optical discs of the same type vary depending onmanufacturers and because of temperatures of a use environment, anoperational environment of a laser, and the like, an optimal recordingwaveforms vary. Therefore, parameters (intensities, pulse widths, andthe like) of the recording waveforms used when information is recordedon the optical disc are adjusted by a result of the test recording.

Thereafter, management information and user data are recorded in the RMAarea and the data area, respectively. The management informationincludes information or the like representing a specific recorded area(record-end position) in the data area. Depending on the progress ofrecording of user data, the management information is updated into thelatest management information. Since the part cannot be rewritten on therecordable DVD once information is recorded, a remaining capacity of theRMA area decreases each time the management information is updated.Depending on a method of updating management information, beforerecording in the entire area of the data area is completed, the RMA areamay not have any more unrecorded areas. When the RMA area does not havean unrecorded area, the management information cannot be updated.Therefore, a recording operation for the data area must be stopped.

On the other hand, in the DVD device described above, a recordingwaveform changes. Depending on a recording position on a disc, anoptimum recording waveform changes due to a change in temperature oraging. In order to adjust the recording waveform depending on thesechanges, in the DVD device, test recording is performed in the PCA areato adjust parameters of the recording waveform. Like the updating of themanagement information, each time the test recording is performed, theremaining capacity of the PCA area decreases. Depending on ways ofexecuting the test recording, the PCA area may not have any moreunrecorded areas before recording in the entire area of the data area iscompleted. When there is no unrecorded area in the PCA area, a recordingoperation must be stopped, or the user data and the managementinformation must be recorded without adjusting the recording waveform.Sufficiently reliable information cannot be reproduced from a part onwhich the information is recorded with an unadjusted recording waveform.

In order to prevent shortage of the RMA area or shortage of the PCAarea, the large capacity of the RMA area or the PCA area may be reservedin advance. However, in this case, the capacity of the data areareduces. As a result, even though the unrecorded areas in the RMA areaand the PCA area sufficiently remain, the capacity of the data area maynot be large enough.

On the other hand, in order to increase a recording capacity, thestandards of a next-generation DVD in which the diameter of a beam spotis narrowed by shortening the wavelength of a laser beam or increasing anumerical aperture NA to increase a recording capacity have beenproposed. As a method of increasing a recording capacity, a single-sidedmultilayer storage medium is also proposed. That is, in addition to thenarrowing down of the beam spot, a plurality of recording layers areformed on one side of a disc, an objective lens is moved in anoptical-axis direction to focus the beam on the respective layers, sothat recording and reproducing can be performed on the respectiverecording layers (for example, see Jpn. Pat. Appln. KOKAI PublicationNo. 2004-206849 (paragraphs 0036 to 0041, FIG. 1)).

The single-sided multilayer storage medium has a problem calledinterlayer crosstalk which does not occur in a single-sided single-layerstorage medium. For descriptive simplification, a dual layer medium willbe exemplified. On a single-sided dual layer storage medium, a laserbeam is focused on the respective layers from a single read surface. Alayer which is close to the read surface is called layer 0, and a layerwhich is far from the read surface is called layer 1. When the beam isfocused on each layer, some laser beam is irradiated on a layer exceptfor a target layer. Therefore, a reflected beam from the layer exceptfor the target layer is mixed with a reproducing signal at the time ofreproducing, interlayer crosstalk occurs. The interlayer crosstalkcauses a problem not only at the time of reproducing but also at thetime of recording.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A general architecture that implements the various feature of theinvention will now be described with reference to the drawings. Thedrawings and the associated descriptions are provided to illustrateembodiments of the invention and not to limit the scope of theinvention.

FIGS. 1A and 1B are exemplary views showing a standard phase shiftrecording film structure and an organic dye recording film structure;

FIG. 2 is an exemplary view showing a specific structural formula of thespecific content “(A3) azo-metal complex+Cu” of the information storagemedium constituent elements;

FIG. 3 is an exemplary view illustrating an example of opticalabsorption spectrum characteristics of an organic dye recording materialfor use in a current DVD-R disc;

FIGS. 4A and 4B are exemplary views each showing comparison of shapes ofrecording films formed in a pre-pit area or a pre-groove area 10 in thephase shift recording film and the organic dye recording film;

FIGS. 5A and 5B are exemplary views each showing a specific plasticdeformation state of a transparent substrate 2-2 at a position of arecording mark 9 in a write-once type information storage medium using aconventional organic dye material;

FIGS. 6A, 6B and 6C are exemplary views relating to a shape ordimensions of a recording film in which a principle of recording iseasily established;

FIGS. 7A, 7B and 7C are exemplary views each showing a shape anddimensions of the recording film;

FIG. 8 is an exemplary view illustrating one embodiment of aninformation recording/reproducing apparatus according to the presentinvention;

FIG. 9 is an exemplary view showing a detailed structure of peripheralportions including a sync code position sampling section 145 shown inFIG. 8;

FIG. 10 is an exemplary view illustrating polarity of a detection signaldetected from the “H-L” recording film and the “L-H” recording film;

FIG. 11 is an exemplary view showing light absorption spectrumcharacteristics in an unrecorded state of the “L-H” recording film;

FIG. 12 is an exemplary view showing a change of light absorptionspectrum characteristics in a recorded state and an unrecorded state ofthe “L-H” recording film;

FIG. 13 is an exemplary general structural formula of a cyanine dyeutilized for a cation portion of the “L-H” recording film;

FIG. 14 is an exemplary view showing an example of an internal structureand dimensions of an information storage medium;

FIGS. 15A, 15B, 15C and 15D are exemplary views each showing an internaldata structure of an RMD duplication zone RDZ and a recording managementzone RMZ located in a write-once type information storage medium;

FIGS. 16A, 16B, 16C and 16D are exemplary views each showing anotherembodiment which is different from

FIGS. 17A, 17B, 17C and 17D are exemplary views each illustrating astructure of a border area in the write-once type information storagemedium;

FIGS. 18A, 18B, 18C and 18D are exemplary views each showing an internaldata structure of a control data zone CDZ and an R physical informationzone RIZ;

FIG. 19 is an exemplary view showing a comparison of the contents ofdetailed information recorded in allocation place information on a dataarea DTA;

FIG. 20 is an exemplary view showing an update condition of recordingposition management data RMD;

FIG. 21 is an exemplary view illustrating 180 degree phase modulationand an NRZ technique in wobble modulation;

FIG. 22 is an exemplary view illustrating a relationship between awobble shape and an address bit in an address bit area;

FIGS. 23A, 23B, 23C and 23D are exemplary views illustrating acomparison in positional relationship between a wobble sync pattern andan inside of a wobble data unit;

FIGS. 24A, 24B, 24C, and 24D are exemplary view relating to an internaldata structure of wobble address information in a write-once typeinformation storage medium;

FIG. 25 is an exemplary view illustrating a setting location of amodulation area on the write-once type information storage medium;

FIGS. 26A, 26B, 26C and 26D are exemplary views each illustrating asetting location of a modulation area in a physical segment on thewrite-once type information storage medium;

FIGS. 27A and 27B are exemplary views each illustrating anotherembodiment of the detection signal level conforming to the H format inan “L-H” recording film;

FIG. 28 is an exemplary view illustrating a BCA data structure;

FIGS. 29A, 29B, 29C, 29D, 29E, 29F and 29G are exemplary views eachillustrating an example of the contents of the BCA information recordedin the BCA data area;

FIGS. 30A, 30B, 30C, 30D and 30E are exemplary views each illustrating awobble address format in a write-once type information storage medium;

FIG. 31 shows an exemplary sectional view of a dual layer recordabledisc according to a second embodiment of the present invention;

FIG. 32 shows an exemplary view showing the ray bundle on the otherlayer while reading and writing of a layer of the disc;

FIG. 33 shows an exemplary view showing the clearance to prevent theinfluence of the other layer at the worst case;

FIG. 34 shows an exemplary view showing a physical sector number onLayer 0 and the corresponding recordable physical sectors on Layer 1;

FIG. 35 shows an exemplary view showing the clearance in the number ofphysical sectors;

FIG. 36 shows an exemplary view showing general parameters of write-oncerecording medium;

FIG. 37 shows an exemplary view showing the schematic of lead-in areaand lead-out area;

FIG. 38 shows an exemplary view showing the schematic of original middlearea;

FIG. 39 shows an exemplary view showing the track path;

FIG. 40 shows an exemplary view showing the physical sector layout andnumbering;

FIG. 41 shows an exemplary view showing the layout of address field inWAP (Wobble Address in Periodic position);

FIG. 42 shows an exemplary view showing the primary WDU (Wobble DataUnit) in sync field;

FIG. 43 shows an exemplary view showing the primary WDU in addressfield;

FIG. 44 shows an exemplary view showing the secondary WDU in sync field;

FIG. 45 shows an exemplary view showing the secondary WDU in addressfield;

FIG. 46 shows an exemplary view showing the WDU in unity field;

FIG. 47 shows an exemplary view showing the structure of the lead-inarea;

FIG. 48 shows an exemplary view showing the structure of a control datazone;

FIG. 49 shows an exemplary view showing a structure of a data segment ina control data section;

FIG. 50 shows an exemplary view showing the physical format information;

FIG. 51 shows an exemplary view showing the data area allocation;

FIG. 52 shows an exemplary view showing the layout of the RMD (RecordingManagement Data) duplication zone;

FIG. 53 shows an exemplary view showing the data structure of therecording management data;

FIG. 54 shows an exemplary view showing the RMD field 0;

FIG. 55 shows an exemplary view showing the data area allocation;

FIG. 56 shows an exemplary view showing the renewed data areaallocation;

FIG. 57 shows an exemplary view showing the drive test zone;

FIG. 58 shows an exemplary view showing the RMD field 1 (part 1);

FIG. 59 shows an exemplary view showing the RMD field 1 (part 2);

FIG. 60 shows an exemplary view showing the RMD field 4;

FIG. 61 shows an exemplary view showing the RMD field 5 to RMD field 21;

FIG. 62 shows an exemplary view showing the structure of a physicalsector block in a R-physical format information zone;

FIG. 63 shows an exemplary view showing the physical format information;

FIG. 64 shows an exemplary view showing the data area allocation;

FIGS. 65A, 65B and 65C shows exemplary views showing the structure ofthe middle area before\after the expansion;

FIG. 66 shows an exemplary view showing the structure of the middle areabefore the expansion;

FIG. 67 shows an exemplary view showing the structure of the middle areaafter small size expansion;

FIG. 68 shows an exemplary view showing the structure of the middle areaafter large size expansion;

FIG. 69 shows an exemplary view showing the number of physical sectorsin guard track zone;

FIG. 70 shows an exemplary view showing the structure of the lead-outarea;

FIGS. 71A and 71B show exemplary views showing the schematic of twoadjacent tracks;

FIG. 72 shows an exemplary view showing start PSN and end PSN of theterminator;

FIGS. 73A and 73B show exemplary views showing a type selection fortrack #i+1;

FIG. 74 shows an exemplary view showing an example of the case that thetype3 physical segment is selected;

FIG. 75 shows an exemplary view showing an example of the procedure toselect the type of the physical segment;

FIG. 76 shows an exemplary view showing a recording procedure of a blankdisc;

FIG. 77 shows an exemplary view showing the example of final areastructure for recording user data on Layer 1;

FIGS. 78A and 78B show exemplary views showing the example of final areastructure for not recording user data on Layer 1;

FIG. 79 shows an exemplary view showing another recording procedure of ablank disc;

FIG. 80 shows an exemplary view showing still another recordingprocedure of a blank disc;

FIG. 81 shows an exemplary view showing a terminator recordingprocedure; and

FIG. 82 shows an exemplary view showing another terminator recordingprocedure.

DETAILED DESCRIPTION

Various embodiments according to the invention will be describedhereinafter with reference to the accompanying drawings. In general,according to one embodiment of the invention, an information recordingmethod which records information on an information storage medium inwhich layer 0 and layer 1 are sequentially arranged as recording layersfrom a read surface; a system lead-in area, a data lead-in area, a dataarea, and a middle area are sequentially arranged from an innercircumference of the layer 0; a system lead-out area, a data lead-outarea, a data area, and a middle area are sequentially arranged from aninner circumference of the layer 1; a guard track zone is arranged on aside of the data area in the data lead-out area; and a reference codezone, an R physical format information zone, a recording managementzone, and a drive test zone are arranged in the data lead-in area of thelayer 0 corresponding to the guard track zone, the method comprisespadding of the guard track zone of the data lead-out area is performedafter padding of the drive test zone of data lead-in area and recordingof the recording management zone, the reference code zone of the datalead-in area, and the R physical format information zone of the datalead-in area.

Hereinafter, embodiments of a recording medium and a method forrecording and reproducing the recording medium according to theinvention will be described with reference to the accompanying drawings.

Summary of Characteristics and Advantageous Effect of the Invention

1) Relationship between track pitch/bit pitch and optimal recordingpower:

Conventionally, in the case of a principle of recording with a substrateshape change, if a track pitch is narrowed, a “cross-write” or a“cross-erase” occurs, and if bit pitches are narrowed, an inter-codecrosstalk occurs. As in the present embodiment, since a principle ofrecording without a substrate shape change is devised, it becomespossible to achieve high density by narrowing track pitches/bit pitches.In addition, at the same time, in the above described principle ofrecording, recording sensitivity is improved, enabling high speedrecording and multi-layering of a recording film because optimalrecording power can be lowly set.

2) In optical recording with a wavelength of 620 nm or less, an ECCblock is composed of a combination of a plurality of small ECC blocksand each item of data ID information in two sectors is disposed in asmall ECC block which is different from another:

According to the invention, as shown in FIG. 1B, a local opticalcharacteristic change in a recording layer 3-2 is a principle ofrecording, and thus, an arrival temperature in the recording layer 3-2at the time of recording is lower than that in the conventionalprinciple of recording due to plastic deformation of a transparentsubstrate 2-2 or due to thermal decomposition or gasification(evaporation) of an organic dye recording material. Therefore, adifference between an arrival temperature and a recording temperature ina recording layer 3-2 at the time of playback is small. In the presentembodiment, an interleaving process between small ECC blocks and data IDallocation are contrived in one ECC block, thereby improvingreproduction reliability in the case where a recording film is degradedat the time of repetitive playback.

3) Recording is carried out by light having a wavelength which isshorter than 620 nm, and a recorded portion has a higher reflectionfactor than a non-recording portion:

Under the influence of absorption spectrum characteristics of a generalorganic dye material, under the control of light having a wavelengthwhich is shorter than 620 nm, the light absorbance is significantlylowered, and recording density is lowered. Therefore, a very largeamount of exposure is required to generate a substrate deformation whichis a principle of recording in a conventional DVD-R. By employing an“Low to High (hereinafter, abbreviated to as L-H) organic dye recordingmaterial” whose reflection factor is increased more significantly thanthat of an unrecorded portion in a portion (recording mark) recorded asin the present embodiment, a substrate deformation is eliminated byforming a recording mark using a “discoloring action due to dissociationof electron coupling”, and recording sensitivity is improved.

4) “L-H” organic dye recording film and PSK/FSK modulation wobblegroove:

Wobble synchronization at the time of playback can be easily obtained,and reproduction reliability of a wobble address is improved.

5) “L-H” organic dye recording film and reproduction signal modulationdegree rule:

A high C/N ratio relating to a reproduction signal from a recording markcan be ensured, and reproduction reliability from the recording mark isimproved.

6) Light reflection factor range in “L-H” organic dye recording film andmirror section:

A high C/N ratio relating to a reproduction signal from a system lead-inarea SYLDI can be ensured and high reproduction reliability can beensured.

7) “L-H” organic dye recording film and light reflection factor rangefrom unrecorded area at the time of on-track:

A high C/N rate relating to a wobble detection signal in an unrecordedarea can be ensured, and high reproduction reliability relevant towobble address information can be ensured.

8) “L-H” organic dye recording film and wobble detection signalamplitude range:

A high C/N ratio relating to a wobble detection signal can be ensuredand high reproduction reliability relevant to wobble address informationcan be ensured.

<<Table of Contents>>

Chapter 0: Description of Relationship between Wavelength and thePresent Embodiment

Wavelength used in the present embodiment.

Chapter 1: Description of Combination of Constituent Elements ofInformation Storage Medium in the Present Embodiment:

Chapter 2: Description of Difference in reproduction signal betweenPhase Change Recording Film and Organic Dye Recording Film

2-1) Difference in Principle of Recording/Recording Film and Differencein Basic Concept Relating to Generation of Reproduction Signal . . .Definition of λ_(max write)

2-2) Difference of Light Reflection Layer Shape in Pre-pit/Pre-grooveArea

Optical reflection layer shape (difference in spin coating andsputtering vapor deposition) and influence on a reproduction signal.

Chapter 3: Description of Characteristics of Organic Dye Recording Filmin the Present Embodiment

3-1) Problem(s) relevant to achievement of high density in write-oncetype recording film (DVD-R) using conventional organic dye material

3-2) Description of basic characteristics common to organic dyerecording films in the present embodiment:

Lower limit value of recording layer thickness, channel bit length/trackpitch in which advantageous effect is attained in the invention,repetitive playback enable count, optimal reproduction power,

Rate between groove width and land width . . . Relationship with wobbleaddress format

Relationship in recording layer thickness between groove section andland section

Technique of improving error correction capability of recordinginformation and combination with PRML

3-3) Recording characteristics common to organic dye recording films inthe present embodiment

Upper limit value of optimal recording power

3-4) Description of characteristics relating to a “High to Low(hereinafter, abbreviated to as H-L)” recording film in the presentembodiment:

Upper limit value of reflection factor in unrecorded layer

Relationship between a value of λ_(max write) and a value of λl_(max)(absorbance maximum wavelength at unrecorded/recorded position)

Relative values of reflection factor and degree of modulation atunrecorded/recorded position and light absorption values at reproductionwavelength . . . n·k range

Relationship in upper limit value between required resolutioncharacteristics and recording layer thickness

Chapter 4: Description of Reproducing Apparatus or Recording/ReproducingApparatus and Recording Condition/Reproducing Circuit

4-1) Description of structure and characteristics of reproducingapparatus or recording/reproducing apparatus in the present embodiment:Use wavelength range, NA value, and RIM intensity

4-2) Description of reproducing circuit in the present embodiment

4-3) Description of recording condition in the present embodiment

Chapter 5: Description of Specific Embodiments of Organic Dye RecordingFilm in the Present Embodiment

5-1) Description of characteristics relating to “L-H” recording film inthe present embodiment

Principle of recording and reflection factor and degree of modulation atunrecorded/recorded position

5-2) Characteristics of light absorption spectra relating to “L-H”recording film in the present embodiment:

Condition for setting maximum absorption wavelength λ_(max write), valueof Al₄₀₅ and a value of Ah₄₀₅

5-3) Anion portion: Azo metal complex+cation portion: Dye

5-4) Use of “copper” as azo metal complex+main metal:

Light absorption spectra after recorded are widening in an “H-L”recording film, and are narrowed in an “L-H” recording film.

Upper limit value of maximum absorption wavelength change amount beforeand after recording:

A maximum absorption wavelength change amount before and after recordingis small, and absorbance at a maximum absorption wavelength changes.

Chapter 6: Description Relating to Pre-groove shape/pre-pit shape incoating type organic dye recording film and on light reflection layerinterface

6-1) Light reflection layer (material and thickness):

Thickness range and passivation structure . . . Principle of recordingand countermeasures against degradation (Signal is degraded more easilythan substrate deformation or than cavity)

6-2) Description relating to pre-pit shape in coating type organic dyerecording film and on light reflection layer interface:

Advantageous effect achieved by widening track pitch/channel bit pitchin system lead-in area:

Reproduction signal amplitude value and resolution in system lead-inarea:

Rule on step amount at land portion and pre-pit portion in lightreflection layer 4-2:

6-3) Description relating to pre-groove shape in coating type organicdye recording film and on light reflection layer interface:

Rule on step amount at land portion and pre-groove portion in lightreflection layer 4-2:

Push-pull signal amplitude range:

Wobble signal amplitude range (combination with wobble modulationsystem)

Chapter 7: Description of First Next-Generation Optical Disc: HD DVDSystem (Hereinafter, Referred to as H Format):

Principle of recording and countermeasure against reproduction signaldegradation (Signal is degraded more easily than substrate deformationor than cavity):

Error Correction Code (ECC) structure, PRML (Partial Response MaximumLikelihood) System:

Relationship between a wide flat area in the groove and wobble addressformat.

In the write-once recording, overwriting is carried out in a VFO areawhich is non-data area.

Influence of DC component change in overwrite area is reduced. Inparticular, advantageous effect on “L-H” recording film is significant.

Now, a description of the present embodiment will be given here.

Chapter 0: Description of Relationship between Use Wavelength and thePresent Embodiment

As a write-once type optical disc obtained by using an organic dyematerial for a recording medium, there has been commercially available aCD-R disc using a recording/reproducing laser light source wavelength of780 nm and a DVD-R disc using a recording/reproducing laser light beamwavelength of 650 nm. Further, in a next-generation write-once typeinformation storage medium having achieved high density, it is proposedthat a laser light source wavelength for recording or reproducing, whichis close to 405 nm (namely, in the range of 355 nm to 455 nm), is usedin either of H format (D1) and B format (D2). In a write-once typeinformation storage medium using an organic dye material,recording/reproducing characteristics sensitively changes due to aslight change of a light source wavelength. In principle, density isincreased in inverse proportion to a square of a laser light sourcewavelength for recording/reproducing, and thus, it is desirable that ashorter laser light source wavelength be used for recording/reproducing.However, for the above described reason, an organic dye materialutilized for a CD-R disc or a DVD-R disc cannot be used as a write-oncetype information storage medium for 405 nm. Moreover, because 405 nm isclose to an ultraviolet ray wavelength, there can easily occur adisadvantage that a recording material “which can be easily recordedwith a light beam of 405 nm”, is easily changed in characteristics dueto ultraviolet ray irradiation, lacking a long period stability.Characteristics are significantly different from each other depending onorganic dye materials to be used, and thus, it is difficult to determinethe characteristics of these dye materials in general.

As an example, the foregoing characteristics will be described by way ofa specific wavelength. With respect to an organic dye recording materialoptimized with a light beam of 650 nm in wavelength, the light to beused becomes shorter than 620 nm, recording/reproducing characteristicssignificantly change. Therefore, in the case where arecording/reproducing operation is carried out with a light beam whichis shorter than 620 nm in wavelength, there is a need for newdevelopment of an organic dye material which is optimal to a lightsource wavelength of recording light or reproducing light. An organicdye material of which recording can be easily carried out with a lightbeam shorter than 530 nm in wavelength easily causes characteristicdegradation due to ultraviolet ray irradiation, lacking long periodstability. In the present embodiment, a description will be given withrespect to an embodiment relevant to an organic recording materialsuitable to use in close to 405 nm. Namely, a description will be givenwith respect to an embodiment relating to an organic recording materialwhich can be stably used in the range of 355 nm to 455 nm inconsideration of a fluctuation of a light emitting wavelength whichdepends on manufacturers of semiconductor laser light sources. That is,the scope of the present embodiment corresponds to a light beam which isadapted to a light source of 620 nm in wavelength, and desirably, whichis shorter than 530 nm in wavelength (ranging from 355 nm to 455 nm in adefinition in the narrowest range).

In addition, the optical recording sensitivity due to light absorptionspectra of an organic dye material is also influenced by a recordingwavelength. An organic dye material suitable for long period stabilityis easily reduced in light absorbance relevant to a light beam which isshorter than 620 nm in wavelength. In particular, the light absorbanceis significantly lowered with respect to a light beam which is shorterthan 620 nm in wavelength, and in particular, is drastically reducedwith respect to a light beam which is shorter than 530 nm in wavelength.Therefore, in the case where recording is carried out with a laser lightbeam ranging from 355 nm to 455 nm in wavelength, which is the severestcondition, recording sensitivity is impaired because the lightabsorbance is low, and there is a need for a new design employing a newprinciple of recording as shown in the present embodiment.

The size of a focusing spot used for recording or reproducingapplication is reduced in proportion to a wavelength of a light beam tobe used. Therefore, from only a standpoint of the focusing spot size, inthe case where a wavelength is reduced to the above described value, anattempt is made to reduce a track pitch or channel bit length by awavelength component with respect to a current DVD-R disc (usewavelength: 650 nm) which is a conventional technique. However, asdescribed later in “3-2-A] Scope requiring application of techniqueaccording to the present embodiment”, as long as a principle ofrecording in a conventional write-once type information storage mediumsuch as a DVD-R disc is used, there is a problem that a track pitch or achannel bit length cannot be reduced. A track pitch or a channel bitlength can be reduced in proportion to the above described wavelength byutilizing a technique devised in the present embodiment described below.

Chapter 1: Description of Combination of Constituent Elements ofInformation Storage Medium in the Present Embodiment

In the present embodiment, there exists a great technical feature inthat an organic recording medium material (organic dye material) adaptedto a light source of 620 nm or less in wavelength has been devised. Suchan organic recording medium (organic dye material) has a uniquecharacteristic (Low to High characteristic) that a light reflectionfactor increases in a recording mark, which does not exist in aconventional CD-R disc or a DVD-R disc. Therefore, a technical featureof the present embodiment and a novel effect attained thereby occurs ina structure, dimensions, or format (information recording format)combination of the information storage medium which produces moreeffectively the characteristics of the organic recording material(organic dye materials) shown in the present embodiment. The informationstorage medium in the present embodiment has the following constituentelements:

A] an organic dye recording film;

B] a pre-format (such as pre-groove shape/dimensions or pre-pitshape/dimensions);

C] a wobble condition (such as wobble modulation method and wobblechange shape, wobble amplitude, and wobble allocating method); and

D] a format (such as format for recording data which is to be recordedor which has been recorded in advance in information storage medium).

Specific embodiments of constituent elements are as follows:

A1) maximum absorption wavelength λ_(max)

A2) recording mark polarity

A3) azo metal complex+Cu

A4) azo metal complex:anion+dye:cation

A5) arbitrary coat-type recording film

B1) pre-groove shape (for track pitch)

B2) pre-pit shape (for track pitch)

B3) arbitrary groove shape and arbitrary pit shape

C1) PSK

C2) FSK

C3) STW

C4) arbitrary modulation system

C5) wobble amplitude amount

C6) arbitrary amplitude amount

D1) write-once recording method

D2) H format

D3) B format

D4) another format

D5) arbitrary recording method and a format in a write-once medium.

Hereinafter, a description will be given with respect to a combinationstate of individual embodiments at a stage of explaining theembodiments. With respect to constituent elements, which do not specifya combination, it denotes that the following characteristics areemployed:

A5) an arbitrary coat-type recording film;

B3) an arbitrary groove shape and an arbitrary pit shape;

C4) an arbitrary modulation system;

C6) an arbitrary amplitude amount; and

D5) an arbitrary recording method and a format in a write-once medium.

Chapter 2: Description of Difference in reproduction signal betweenPhase Change Recording Film and Organic Dye Recording Film

2-1) Difference in Principle of Recording/Recording Film and Differencein Basic Concept Relating to Generation of Reproduction Signal

FIG. 1A shows a standard phase change recording film structure (mainlyused for a rewritable-type information storage medium), and FIG. 1Bshows a standard organic dye recording film structure (mainly used for awrite-once type information storage medium). In the description of thepresent embodiment, a whole recording film structure excludingtransparent substrates 2-1 and 2-2 shown in FIGS. 1A and 1B (includinglight reflection layers 4-1 and 4-2) is defined as a “recording film”,and is discriminated from recording layers 3-1 and 3-2 in which arecording material is disposed. With respect to a recording materialusing a phase change, in general, an optical characteristic changeamount in a recorded area (in a recording mark) and an unrecorded area(out of a recording mark) is small, and thus, there is employed anenhancement structure for enhancing a relative change rate of areproduction signal. Therefore, in a phase change recording filmstructure, as shown in FIG. 1A, an undercoat intermediate layer 5 isdisposed between the transparent substrate 2-1 and a phase change typerecording layer 3-1, and an upper intermediate layer 6 is disposedbetween the light reflection layer 4-2 and the phase change typerecording layer 3-1. In the invention, as a material for the transparentsubstrates 2-1 and 2-2, there is employed a polycarbonate PC or anacrylic PMMA (poly methyl methacrylate) which is a transparent plasticmaterial. A center wavelength of a laser light beam 7 used in thepresent embodiment is 405 nm, and refractive index n₂₁, n₂₂ of thepolycarbonate PC at this wavelength is close to 1.62.

Standard refractive index n₃₁ and absorption coefficient k₃₁ in 405 nmat GeSbTe (germanium antimony tellurium) which is most generally used asa phase change type recording material are n₃₁≅1.5 and k₃₁≅2.5 in acrystalline area, whereas they are n₃₁≅2.5 and k₃₁≅1.8 in an amorphousarea. Thus, a refractive index (in the amorphous area) of a phase changetype recording medium is different from a refractive index of thetransparent substrate 2-1, and reflection of a laser light beam 7 on aninterface between the layers is easily occurred in a phase changerecording film structure. As described above, for the reasons why (1) aphase change recording film structure takes an enhancement structure;and (2) a refractive index difference between the layers is great or thelike, a light reflection amount change at the time of reproduction froma recording mark recorded in a phase change recording film (adifferential value of a light reflection amount from a recording markand a light reflection amount from an unrecorded area) can be obtainedas an interference result of multiple reflection light beams generatedon an interface between the undercoat intermediate layer 5, therecording layer 3-1, the upper intermediate layer 6, and the lightreflection layer 4-2. In FIG. 1A, although the laser light beam 7 isapparently reflected on an interface between the undercoat intermediatelayer 5 and the recording layer 3-1, an interface between the recordinglayer 3-1 and the upper intermediate layer 6, and an interface betweenthe upper intermediate layer 6 and the light reflection layer 4-2, inactuality, a reflection light amount change is obtained as aninterference result between a plurality of multiple reflection lightbeams.

In contrast, an organic dye recording film structure takes a very simplelaminate structure made of an organic dye recording layer 3-2 and alight reflection layer 4-2. An information storage medium (optical disc)using this organic dye recording film is called a write-once typeinformation storage medium, which enables only one time of recording.However, unlike a rewritable-type information storage medium using thephase change recording medium, this medium cannot carry out an erasingprocess or a rewriting process of information which has been recordedonce. A refractive index at 405 nm of a general organic dye recordingmaterial is often close to n₃₂≅1.4 (n₃₂=1.4 to 1.9 in the refractiveindex range at 405 nm of a variety of organic dye recording materials)and an absorption coefficient is often close to k₃₂≅0.2 (k₃₂≅0.1 to 0.2in the absorption coefficient range at 405 nm of a variety of organicdye recording materials). Because a refractive index difference betweenthe organic dye recording material and the transparent substrate 2-2 issmall, there hardly occurs a light reflection amount on an interfacebetween the recording layer 3-2 and the transparent substrate 2-2.Therefore, an optical reproduction principle of an organic colorrecording film (reason why a reflection light amount change occurs) isnot “multiple interference” in a phase change recording film, and a mainfactor is a “light amount loss (including interference) midway of anoptical path with respect to the laser light beam 7 which comes backafter being reflected in the light reflection layer 4-2”. Specificreasons which cause a light amount loss midway of an optical pathinclude an “interference phenomenon due to a phase difference partiallycaused in the laser light 7” or an “optical absorption phenomenon in therecording layer 3-2”. The light reflection factor of the organic dyerecording film in an unrecorded area on a mirror surface on which apre-groove or a pre-pit does not exist is featured to be simply obtainedby a value obtained by subtracting an optical absorption amount when therecording layer 3-2 is passed from the light reflection factor of thelaser light beam 7 in the light reflection layer 4-2. As describedabove, this film is different from a phase change recording film whoselight reflection factor is obtained by calculation of “multipleinterference”.

Light fastness of a recording film (organic dye recording film) of thedisc (High Density recordable DVD (HD DVD-R)) using a blue light laserhaving a wavelength A of 405 nm will be described. The light fastness ofthe HD DVD-R is tested by a device an air cooling xenon lamp which arein accordance with ISO-105-B02. In ISO-105-B02, a temperature of a blackpanel is not higher than 40° C. and a relative humidity is 70 to 80%. Atesting laser beam is irradiated onto the disk in a perpendiculardirection from the top. When all conditions after test are satisfied,the disc is regarded as a proofed disc.

First, a description will be given with respect to a principle ofrecording, which is used in a current DVD-R disc as a conventionaltechnique. In the current DVD-R disc, when a recording film isirradiated with the laser light beam 7, the recording layer 3-2 locallyabsorbs energy of the laser light beam 7, and becomes hot. If a specifictemperature is exceeded, the transparent substrate 2-2 is locallydeformed. Although a mechanism, which induces deformation of thetransparent substrate 2-2, is different depending on manufacturers ofDVD-R discs, it is said that this mechanism is caused by:

1) local plastic deformation of the transparent substrate 2-2 due togasification energy of the recording layer 3-2; and

2) transmission of a heat from the recording layer 3-2 to thetransparent substrate 2-2 and local plastic deformation of thetransparent substrate 2-2 due to the heat.

If the transparent substrate 2-2 is locally plastically deformed, therechanges an optical distance of the laser light beam 7 reflected in thelight reflection layer 4-2 through the transparent substrate 2-2, thelaser light beam 7 coming back through the transparent substrate 2-2again. A phase difference occurs between the laser light beam 7 from arecording mark, the laser light beam coming back through a portion ofthe locally plastically deformed transparent substrate 2-2, and a laserlight beam 7 from the periphery of the recording mark, the laser lightbeam coming back through a portion of a transparent substrate 2-2 whichis not deformed, and thus, a light amount change of reflection lightbeam occurs due to interference between these light beams. In addition,in particular, in the case where the above described mechanism of (1)has occurred, a change of a substantial refractive index n₃₂ produced bycavitations of the inside of the recording mark in the recording layer3-2 due to gasification (evaporation), or alternatively, a change of arefractive index n₃₂ produced due to thermal decomposition of an organicdye recording material in the recording mark, also contributes to theabove described occurrence of a phase difference. In the current DVD-Rdisc, until the transparent substrate 2-2 is locally deformed, there isa need for the recording layer 3-2 becoming hot (i.e., at a gasificationtemperature of the recording layer 3-2 in the above described mechanismof (1) or at an internal temperature of the recording layer 3-2 requiredfor plastically reforming the transparent substrate 2-2 in the mechanismof (2)) or there is a need for a part of the recording layer 3-2becoming hot in order to cause thermal decomposition or gasification(evaporation). In order to form a recording mark, there is a need forlarge amount of power of the laser light beam 7.

In order to form the recording mark, there is a necessity that therecording layer 3-2 can absorb energy of the laser light beam 7 at afirst stage. The light absorption spectra in the recording layer 3-2influence the recording sensitivity of an organic dye recording film. Aprinciple of light absorption in an organic dye recording material whichforms the recording layer 3-2 will be described with reference to (A3)of the present embodiment.

FIG. 2 shows a specific structural formula of the specific contents“(A3) azo metal complex+Cu” of the constituent elements of theinformation storage medium. A circular periphery area around a centermetal M of the azo metal complex shown in FIG. 2 is obtained as a lightemitting area 8. When a laser light beam 7 passes through this lightemitting area 8, local electrons in this light emitting area 8 resonateto an electric field change of the laser light beam 7, and absorbsenergy of the laser light beam 7. A value converted to a wavelength ofthe laser light beam with respect to a frequency of an electric fieldchange at which these local electrons resonate most and easily absorbsthe energy is called a maximum absorption wavelength, and is representedby λ_(max). As a range of the light emitting area 8 (resonation range)as shown in FIG. 2 increases, the maximum absorption wavelength λ_(max)is shifted to the long wavelength side. In addition, in FIG. 2, thelocalization range of local electrons around the center metal M (howlarge the center metal M can attract the local electrons to the vicinityof the center) is changed by changing atoms of the center metal M, andthe value of the maximum absorption wavelength λ_(max) changes.

Although it can be predicted that the light absorption spectra of theorganic dye recording material in the case where there exists only onelight emitting area 8 which is absolute 0 degree at a temperature andhigh in purity draws narrow linear spectra in close to a maximumabsorption wavelength λ_(max), the light absorption spectra of a generalorganic recording material including impurities at a normal temperature,and further, including a plurality of light absorption areas exhibit awide light absorption characteristic with respect to a wavelength of alight beam around the maximum absorption wavelength λ_(max).

FIG. 3 shows an example of light absorption spectra of an organic dyerecording material used for a current DVD-R disc. In FIG. 3, awavelength of a light beam to be irradiated with respect to an organicdye recording film formed by coating an organic dye recording materialis taken on a horizontal axis, and absorbance obtained when an organicdye recording film is irradiated with a light beam having a respectivewavelength is taken on a vertical axis. The absorbance used here is avalue obtained by entering a laser light beam having incident intensityIo from the side of the transparent substrate 2-2 with respect to astate in which a write-once type information storage medium has beencompleted (or alternatively, a state in which the recording layer 3-2has been merely formed on the transparent substrate 2-2 (a state thatprecedes forming of the optical reflection layer 4-2 with respect to astructure of FIG. 1B)), and then, measuring reflected laser lightintensity Ir (light intensity It of the laser light beam transmittedfrom the side of the recording layer 3-2). The absorbance Ar (At) isrepresented by:

Ar≡—log₁₀(Ir/Io)   (A-1)

Ar≡−log₁₀(It/Io)   (A-2)

Unless otherwise specified, although a description will be givenassuming that the absorbance denotes absorbance Ar of a reflection shapeexpressed by formula (A-1), it is possible to define absorbance At of atransmission shape expressed by formula (A-2) without being limitedthereto in the present embodiment. In the embodiment shown in FIG. 3,there exist a plurality of light absorption areas, each of whichincludes the light emitting area 8, and thus, there exist a plurality ofpositions at which the absorbance becomes maximal. In this case, thereexist a plurality of maximum absorption wavelength λ_(max) when theabsorbance takes a maximum value. A wavelength of the recording laserlight in the current DVD-R disc is set to 650 nm. In the case wherethere exist a plurality of the maximum absorption wavelengths λ_(max) inthe present embodiment, a value of the maximum absorption wavelengthλ_(max) which is the closest to the wavelength of the recording laserlight beam becomes important. Therefore, only in the description of thepresent embodiment, the value of the maximum absorption wavelengthλ_(max) set at a position which is the closest to the wavelength of therecording laser light beam is defined as “λ_(max) write”; and isdiscriminated from another λ_(max) (λ_(max 0)).

2-2) Difference of light reflection layer shape in pre-pit/pre-groovearea

FIGS. 4A and 4B each show a comparison in shape when a recording film isformed in a pre-pit area or a pre-groove area 10. FIG. 4A shows a shaperelevant to a phase change recording film. In the case of forming any ofthe undercoat intermediate layer 5, the recording layer 3-1, the upperintermediate layer 6, and the light reflection layer 4-1 as well, any ofmethods of sputtering vapor deposition, vacuum vapor deposition, or ionplating is used in vacuum. As a result, in all of the layers,irregularities of the transparent substrate 2-1 are duplicatedcomparatively faithfully. For example, in the case where a sectionalshape in the pre-pit area or pre-groove area 10 of the transparentsubstrate 2-1 is rectangular or trapezoidal, the sectional shape of therecording layer 3-1 and the light reflection layer 4-1 each is alsorectangular or trapezoidal.

FIG. 4B shows a general recording film sectional shape of a currentDVD-R disc which is a conventional technique as a recording film in thecase where an organic dye recording film has been used. In this case, asa method for forming the recording film 3-2, there is used a methodcalled spin coating (or spinner coating) which is completely differentfrom that shown in FIG. 4A. The spin coating used here denotes a methodfor dissolving in an organic solvent an organic dye recording materialwhich forms the recording layer 3-2; applying a coating onto thetransparent substrate 2-2; followed by rotating the transparentsubstrate 2-2 at a high speed to spread a coating agent to the outerperiphery side of the transparent substrate 2-2 by a centrifugal force;and gasifying the organic solvent, thereby forming the recording layer3-2. Using this method, a process for coating the organic solvent isused, and thus, a surface of the recording layer 3-2 (an interface withthe light reflection layer 2-2) is easily flattened. As a result, thesectional shape on the interface between the light reflection layer 2-2and the recording layer 3-2 is obtained as a shape which is differentfrom the shape of the surface of the transparent substrate 2-2 (aninterface between the transparent substrate 2-2 and the recording layer3-2). For example, in a pre-groove area in which the sectional shape ofthe surface of the transparent substrate 2-2 (an interface between thetransparent substrate 2-2 and the recording layer 3-2) is rectangular ortrapezoidal, the sectional shape on the interface between the lightreflection layer 2-2 and the recording layer 3-2 is formed in asubstantially V-shaped groove shape. In a pre-pit area, the abovesectional shape is formed in a substantially conical side surface shape.Further, at the time of spin coating, an organic solvent is easilycollected at a recessed portion, and thus, the thickness Dg of therecording layer 3-2 in the pre-pit area or pre-groove area 10 (i.e., adistance from a bottom surface of the pre-pit area or pre-groove area toa position at which an interface relevant to the light reflection layer2-2 becomes the lowest) is larger than the thickness D1 in a land area12 (Dg>D1). As a result, an amount of irregularities on an interfacebetween the transparent substrate 2-2 and the recording area 3-2 in thepre-pit area or pre-groove area 10 becomes substantially smaller than anamount of irregularities on the transparent substrate 2-2 and therecording layer 3-2.

As described above, the shape of irregularities on the interface betweenthe light reflection layer 2-2 and the recording layer 3-2 becomes bluntand an amount of irregularities becomes significantly small. Thus, inthe case where the shape and dimensions of irregularities on a surfaceof the transparent substrate 2 (pre-pit area or pre-groove area 10) areequal to each other depending on a difference in method for forming arecording film, the diffraction intensity of the reflection light beamfrom the organic dye recording film at the time of laser lightirradiation is degraded more significantly than the diffractionintensity of the reflection light beam from the phase change recordingfilm. As a result, in the case where the shape and dimensions ofirregularities on the surface of the transparent substrate 2 (pre-pitarea or pre-groove area 10) are equal to each other, as compared withuse of the phase change recording film, use of the conventional organicdye recording film is disadvantageously featured in that:

-   -   1) a degree of modulation of a light reproduction signal from        the pre-pit area is small, and signal reproduction reliability        from the pre-pit area is poor;    -   2) a sufficiently large track shift detecting signal is hardly        obtained in accordance with a push-pull technique from the        pre-groove area; and    -   3) a sufficient large wobble detecting signal is hardly obtained        in the case where wobbling occurs in the pre-groove area.

In addition, in a DVD-R disc, specific information such as addressinformation is recorded in a small irregular (pit) shape in a land area,and thus, a width W1 of the land area 12 is larger than a width Wg ofthe pre-pit area or pre-groove area 10 (Wg>W1).

Chapter 3: Description of Characteristics of Organic Dye Recording Filmin the Present Embodiment

3-1) Problem(s) relevant to achievement of high density in write-oncetype recording film (DVD-R) using conventional organic dye material

As has been described in “2-1) Difference in recordingprinciple/recording film structure and difference in basic conceptrelating to generation of reproducing signal”, a general principle ofrecording of a current DVD-R and CD-R, which is a write-once typeinformation storage medium using a conventional organic dye materialincludes “local plastic deformation of transparent substrate 2-2” or“local thermal decomposition or “gasification” in recording layer 3-2”.FIGS. 5A and 5B each show a plastic deformation state of a specifictransparent substrate 2-2 at a position of a recording mark 9 in awrite-once type information storage medium using a conventional organicdye material. There exist two types of typical plastic deformationstates. There are two cases, i.e., a case in which, as shown in FIG. 5A,a depth of a bottom surface 14 of a pre-groove area at the position ofthe recording mark 9 (an amount of step relevant to an adjacent landarea 12) is different from a depth of a bottom surface of a pre-groovearea 11 in an unrecorded area (in the example shown in FIG. 5A, thedepth of the bottom surface 14 in the pre-groove area at the position ofthe recording mark 9 is shallower than that in the unrecorded area); anda case in which, as shown in FIG. 5B, a bottom surface 14 in apre-groove area at the position of the recording mark 9 is distorted andis slightly curved (the flatness of the bottom surface 14 is distorted:In the example shown in FIG. 5B, the bottom surface 14 in the pre-groovearea at the position of the recording mark 9 is slightly curved towardthe lower side). Both of these cases are featured in that a plasticdeformation range of the transparent substrate 2-2 at the position ofthe recording mark 9 covers a wide range. In the current DVD-R discwhich is a conventional technique, a track pitch is 0.74 μm, and achannel bit length is 0.133 μm. In the case of a large value of thisdegree, even if the plastic deformation range of the transparentsubstrate 2-2 at the position of the recording mark 9 covers a widerange, comparatively stable recording and reproducing processes can becarried out.

However, if the track pitch is narrower than 0.74 μm described above,the plastic deformation range of the transparent substrate 2-2 at theposition of the recording mark 9 covers a wide range, and thus, theadjacent tracks are adversely affected, and the recording mark 9 of theexisting adjacent track is substantially erased (cannot be reproduced)due to a “cross-write” or overwrite in which the recording mark 9 widensto the adjacent tracks. In addition, in a direction (circumferentialdirection) along the tracks, if the channel bit length is narrower than0.133 μm, there occurs a problem that inter-code interference appears;an error rate at the time of reproduction significantly increases; andthe reliability of reproduction is lowered.

3-2) Description of basic characteristics common to organic dyerecording film in the present embodiment

3-2-A] Range requiring application of technique according to the presentembodiment

As shown in FIGS. 5A and 5B, in a conventional write-once typeinformation storage medium including plastic deformation of thetransparent substrate 2-2 or local thermal decomposition or gasificationphenomenon in the recording film 3-2, a description will be given belowwith respect to what degree of track pitch is narrowed when an adverseaffect appears or what degree of channel pit length is narrowed when anadverse effect appears and a result obtained after technical discussionhas been carried out with respect to a reason for such an adverseeffect. A range in which an adverse effect starts appearing in the caseof utilizing the conventional principle of recording indicates a range(suitable for the achievement of high density) in which advantageouseffect is attained due to a novel principle of recording shown in thepresent embodiment.

1) Condition of Thickness Dg of Recording Layer 3-2

When an attempt is made to carry out thermal analysis in order totheoretically identify a lower limit value of an allowable channel bitlength or a lower limit value of allowable track pitch, a range of thethickness Dg of a recording layer 3-2 which can be substantiallythermally analyzed becomes important. In a conventional write-once typeinformation storage medium (CD-R or DVD-R) including plastic deformationof the transparent substrate 2-2 as shown in FIGS. 5A and 5B, withrespect to a change of light reflection amount in the case where aninformation reproduction focusing spot is provided in the recording mark8 and in the case where the spot is in an unrecorded area of therecording layer 3-2, the largest factor is “an interference effect dueto a difference in optical distance in the recording mark 9 and inunrecorded area”. In addition, a difference in its optical difference ismainly caused by “a change of the thickness Dg of a physical recordinglayer 3-2 due to plastic deformation of the transparent substrate 2-2 (aphysical distance from an interface between the transparent substrate2-2 and the recording layer 3-2 to an interface between the recordinglayer 3-2 and a light reflection layer 4-2) and “a change of refractiveindex n₃₂ of the recording layer 3-2 in the recording mark 9”.Therefore, in order to obtain a sufficient reproduction signal (changeof light reflection amount) between the recording mark 9 and theunrecorded area, when a wavelength in vacuum of laser light beam isdefined as λ, it is necessary for the value of the thickness 3-2 in theunrecorded area has a size to some extent as compared with λ/n₃₂. Ifnot, a difference (phase difference) in optical distance between therecording mark 9 and the unrecorded area does not appear, and lightinterference effect becomes small. In reality, a minimum condition:

Dg≧λ/8n ₃₂   (1)

must be met, and desirably, a condition that:

Dg≧λ/4n ₃₂   (2)

must be met.

At a time point of current discussion, the vicinity of λ=405 nm isassumed. A value of refractive index n₃₂ of an organic dye recordingmaterial at 405 nm ranges from 1.3 to 2.0. Therefore, as a result ofsubstituting n₃₂=2.0 in formula (1), it is conditionally mandatory thata value of the thickness Dg of the recording layer 3-2 is:

Dg≧25 nm   (3)

Here, discussion is made with respect to a condition when an organic dyerecording layer of a conventional write-once type information storagemedium (CD-R or DVD-R) including plastic deformation of the transparentsubstrate 2-2 has been associated with a light beam of 405 nm. Asdescribed later, in the present embodiment, although a description isgiven with respect to a case in which plastic deformation of thetransparent substrate 2-2 does not occur and a change of an absorptioncoefficient k₃₂ is a main factor of a principle of recording, it isnecessary to carry out track shift detection by using a DPD(Differential Phase Detection) technique from the recording mark 9, andthus, in reality, the change of the refractive index n₃₂ is caused inthe recording mark 9. Therefore, the condition for formula (3) becomes acondition, which should be met, in the present embodiment in whichplastic deformation of the transparent substrate 2-2 does not occur.

From another point of view as well, the range of the thickness Dg can bespecified. In the case of a phase change recording film shown in FIG.4A, when a refractive index of the transparent substrate is n₂₁, a stepamount between a pre-pit area and a land area is λ/(8n₂₁) when thelargest track shift detection signal is obtained by using a push-pulltechnique. However, in the case of an organic dye recording film shownin FIG. 4B, as described previously, the shape on an interface betweenthe recording layer 3-2 and the light reflection layer 4-2 becomesblunt, and a step amount becomes small. Thus, it is necessary toincrease a step amount between a pre-pit area and a land area on thetransparent substrate 2-2 more significantly than λ/(8n₂₂). For example,the refractive index at 405 nm in the case where polycarbonate has beenused as a material for the transparent substrate 2-2 is n₂₂≅1.62, andthus, it is necessary to increase a step amount between the pre-pit areaand the land area more significantly than 31 nm. In the case of using aspin coating technique, if the thickness Dg of the recording layer 3-2in the pre-groove area is greater than a step amount between the pre-pitarea and the land area on the transparent substrate 2-2, there is adanger that thickness D1 of the recording layer 3-2 in a land area 12 iseliminated. Therefore, from the above described discussion result, it isnecessary to meet a condition that:

Dg≧31 nm   (4)

The condition for formula (4) is also a condition, which should be metin the present embodiment in which plastic deformation of thetransparent substrate 2-2 does not occur. Although conditions for thelower limit values have been shown in formulas (3) and (4), the valueDg≅60 nm obtained by substituting n₃₂=1.8 for an equal sign portion informula (2) has been utilized as the thickness Dg of the recording layer3-2 used for thermal analysis.

Then, assuming polycarbonate used as a standard material of thetransparent substrate 2-2, 150° C. which is a glass transitiontemperature of polycarbonate has been set as an estimate value of athermal deformation temperature at the side of the transparent substrate2-2. For discussion using thermal analysis, a value of k₃₂=0.1 to 0.2has been assumed as a value of an absorption coefficient of the organicdye recording film 3-2 at 405 nm. Further, discussion has been made withrespect to a case in which an NA value of a focusing objective lens andan incident light intensity distribution when an objective lens ispassed is NA=60 and H format ((D1):NA=0.65) and B format ((D2):NA=0.85)which is assumed condition in a conventional DVD-R format.

2) Condition for Lower Limit Value of Channel Bit Length

A check has been made for a lengthwise change in a direction along atrack of an area reaching a thermal deformation temperature at the sideof a transparent substrate 2-2 which comes into contact with a recordinglayer 3-2 when recording power has been changed. Discussion has beenmade with respect to a lower limit value of an allowable channel bitlength considering a window margin at the time of reproduction. As aresult, if the channel bit length is slightly lower than 105 nm, it isconsidered that a lengthwise change in a direction along a track in anarea which reaches the thermal deformation temperature at the side ofthe transparent substrate 2-2 occurs according to the slight change ofrecording power, and a sufficient window margin cannot be obtained. Ondiscussion of thermal analysis, an analogous tendency is shown in thecase where the NA value is any one of 0.60, 0.65, and 0.85. Although afocusing spot size is changed by changing the NA value, a possibilitycause is believed to be that a thermal spreading range is wide (agradient of a temperature distribution at the side of the transparentsubstrate 2-2 which comes into contact with the recording layer 3-2) iscomparatively gentle). In the above thermal analysis, the temperaturedistribution at the side of the transparent substrate 2-2 which comesinto contact with the recording layer 3-2 is discussed, and thus, aneffect of the thickness Dg of the recording layer 3-2 does not appear.

Further, in the case where a shape change of the transparent substrate3-3 shown in FIGS. 5A and 5B occurs, a boundary position of a substratedeformation area blurs (is ambiguous), and thus, a window margin islowered more significantly. When a sectional shape of an area in whichthe recording mark 9 is formed is observed by an electron microscope, itis believed that a blurring amount of the boundary position of thesubstrate deformation area increases as the value of the thickness Dg ofthe recording layer 3-2 increases. With respect to the effect of thethermal deformation area length due to the above recording power change,in consideration of the blurring of the boundary position of thissubstrate deformation area, it is considered necessary that the lowerlimit value of the channel bit length allowed for allocation of asufficient window margin is in order of two times of the thickness Dg ofthe recording layer 3-2, and it is desirable that the lower limit valueis greater than 120 nm.

In the foregoing, a description has been principally given with respectto discussion using thermal analysis in the case where thermaldeformation of the transparent substrate 2-2 occurs. There also exists acase in which plastic deformation of the transparent substrate 2-2 isvery small as another principle of recording (mechanism of forming therecording mark 9) in a conventional write-once type information storagemedium (CD-R or DVD-R) and thermal deformation or gasification(evaporation) of the organic dye recording material in the recordinglayer 3-2 mainly occurs. Thus, an additional description will be givenwith respect to such a case. Although the gasification (evaporation)temperature of the organic dye recording material is different dependingon the type of the organic dye material, in general, the temperatureranges 220° C. to 370° C., and a thermal decomposition temperature islower than this range. Although a glass transition temperature 150° C.of a polycarbonate resin has been presumed as an arrival temperature atthe time of substrate deformation in the above discussion, a temperaturedifference between 150° C. and 220° C. is small, and, when thetransparent substrate 2-2 reaches 150° C., the inside of the recordinglayer 3-2 exceeds 220° C. Therefore, although there exists an exceptiondepending on the type of the organic recording material, even in thecase where plastic deformation of the transparent substrate 2-2 is verysmall and thermal decomposition or gasification (evaporation) of theorganic dye recording material in the recording layer mainly occurs,there is obtained a result which is substantially identical to the abovediscussion result.

When the discussion result relating to the above channel bit length issummarized, in the conventional write-once type information storagemedium (CD-R or DVD-R) including plastic deformation of the transparentsubstrate 2-2, it is considered that, when a channel bit length isnarrower than 120 nm, the lowering of a window margin occurs, andfurther, if the length is smaller than 105 nm, stable reproductionbecomes difficult. That is, when the channel bit is smaller than 120 nm(105 nm), advantageous effect is attained by using a novel principle ofrecording shown in the present embodiment.

3) Condition for Lower Limit Value of Track Pitches

When a recording layer 3-2 is exposed at recording power, energy isabsorbed in the recording layer 3-2, and a high temperature is obtained.In a conventional write-once type information storage medium (CD-R orDVD-R), it is necessary to absorb energy in the recording layer 3-2until the transparent substrate 3-2 has reached a thermal deformationtemperature. A temperature at which a structural change of the organicdye recording material occurs in the recording layer 3-2 and a value ofa refractive index n₃₂ or an absorption coefficient k₃₂ starts itschange is much lower than an arrival temperature for the transparentsubstrate 2-2 to start thermal deformation. Therefore, the value of therefractive index n₃₂ or absorption coefficient k₃₂ changes in acomparatively wide range in the recording layer 3-2 at the periphery ofa recording mark 9, which is thermal deformed at the side of thetransparent substrate 2-2, and this change seems to cause “cross-write”or “cross-erase” for the adjacent tracks. It is possible to set a lowerlimit value of track pitch in which “cross-write” or “cross-erase” doesnot occur with the width of an area which reaches a temperature whichchanges the refractive index n₃₂ or absorption coefficient k₃₂ in therecording layer 3-2 when the transparent substrate 2-2 exceeds a thermaldeformation temperature. From the above point of view, it is consideredthat “cross-write” or “cross-erase” occurs in location in which thetrack pitch is equal to or smaller than 500 nm. Further, inconsideration of an effect of warping or inclination of an informationstorage medium or a change of recording power (recording power margin),it can be concluded difficult to set the track pitch to 600 nm or lessin the conventional write-once type information storage medium (CD-R orDVD-R) in which energy is absorbed in the recording layer 3-2 until thetransparent substrate 2-2 has reached a thermal deformation temperature.

As described above, even if the NA value is changed from 0.60, 0.65, andthen, to 0.85, substantially similar tendency is shown because thegradient of the temperature distribution in the peripheral recordinglayer 3-2 when the transparent substrate 2-2 has reached a thermaldeformation temperature at a center part is comparatively gentle, andthe thermal spread range is wide. In the case where plastic deformationof the transparent substrate 2-2 is very small and thermal decompositionor gasification (evaporation) of the organic dye recording material inthe recording layer 3-2 mainly occurs as another principle of recording(mechanism of forming the recording mark 9) in the conventionalwrite-once type information storage medium (CD-R or DVD-R), as has beendescribed in the section “(2) Condition for lower limit value of channelbit”, the value of track pitch at which “cross-write” or “cross-erase”starts is obtained as a substantially analogous result. For the abovedescribed reason, advantageous effect is attained by using a novelprinciple of recording shown in the present embodiment when the trackpitch is set to 600 nm (500 nm) or lower.

3-2-B] Basic characteristics common to organic dye recording material inthe invention

As described above, in the case where plastic deformation of thetransparent substrate 2-2 is very small and thermal decomposition orgasification (evaporation) of the organic dye recording material in therecording layer 3-2 mainly occurs as another principle of recording(mechanism of forming the recording mark 9) in the conventionalwrite-once type information storage medium (CD-R or DVD-R), there occursa problem that a channel bit length or track pitches cannot be narrowedbecause the inside of the recording layer 3-2 or a surface of thetransparent substrate 2-2 reaches a high temperature at the time offorming the recording mark 9. In order to solve the above describedproblem, the present embodiment is featured in “inventive organic dyematerial” in which “a local optical characteristic change in therecording layer 3-2, which occurs at a comparatively low temperature, isa principle of recording” and “setting environment (recording filmstructure or shape) in which the above principle of recording easilyoccurs without causing a substrate deformation and gasification(evaporation) in the recording layer 3-2. Specific characteristics ofthe present embodiment can be listed below.

α] Optical characteristic changing method inside of recording layer 3-2

Chromogenic Characteristic Change

Change of light absorption sectional area due to qualitative change oflight emitting area 8 (FIG. 2) or change of molar molecule lightabsorption coefficient

The light emitting area 8 is partially destroyed or the size of thelight emitting area 8 changes, whereby a substantial light absorptionsectional area changes. In this manner, an amplitude (absorbance) at aposition of λ_(max) write changes in the recording mark 9 while aprofile (characteristics) of light absorption spectra (FIG. 3) itself ismaintained.

Change of electronic structure (electron orbit) relevant to electronswhich contribute to a chromogenic phenomenon

Change of light absorption spectra (FIG. 3) based on discoloring actiondue to cutting of local electron orbit (dissociation of local molecularbonding) or change of dimensions or structure of light emitting area 8(FIG. 2)

Intra-molecular (inter-molecular) change of orientation or array

Optical characteristic change based on orientation change in azo metalcomplex shown in FIG. 2, for example

Molecular structure change in molecule

For example, discussion is made with respect to an organic dye materialwhich causes either of dissociation between anion portion and cationportion, thermal decomposition of either of anion portion and cationportion, and a tar phenomenon that a molecular structure itself isdestroyed, and carbon atoms are precipitated (denaturing to black coaltar). As a result, the refractive index n₃₂ or absorption coefficientk₃₂ in the recording mark 9 is changed with respect to an unrecordedarea, enabling optical reproduction.

β] Setting recording film structure or shape, making it easy to stablycause an optical characteristic change of [α] above:

The specific contents relating to this technique will be described indetail in the section “3-2-C] Ideal recording film structure which makesit easy to cause a principle of recording shown in the presentembodiment” and subsequent.

γ] Recording power is reduced in order to form recording mark in a statein which inside of recording layer or transparent substrate surface iscomparatively low at temperature

The optical characteristic change shown in [α] above occurs at atemperature lower than a deformation temperature of the transparentsubstrate 2-2 or a gasification (evaporation) temperature in therecording layer 3-2. Thus, the exposure amount (recording power) at thetime of recording is reduced to prevent the deformation temperature frombeing exceeded on the surface of the transparent substrate 2-2 or thegasification (evaporation) temperature from being exceeded in therecording layer 3-2. The contents will be described later in detail inthe section “3-3) Recording characteristics common to organic dyerecording layer in the present embodiment”. In addition, in contrast, itbecomes possible to determine whether or not the optical characteristicchange shown in [α] above occurs by checking a value of the optimalpower at the time of recording.

δ] Electron structure in a light emitting area is stabilized, andstructural decomposition relevant to ultraviolet ray or reproductionlight irradiation is hardly generated

When ultraviolet ray is irradiated to the recording layer 3-2 orreproduction light is irradiated to the recording layer 3-2 at the timeof reproduction, a temperature size in the recording layer 3-2 occurs.There is a request for a seemingly contradictory performance thatcharacteristic degradation relevant to such a temperature rise isprevented and recording is carried out at a temperature lower than asubstrate deformation temperature or a gasification (evaporation)temperature in the recording layer 3-2. In the present embodiment, theabove described seemingly contradictory performance is ensured by“stabilizing an electron structure in a light emitting area”. Thespecific technical contents will be described in “Chapter 4 SpecificDescription of Embodiments of Organic Dye Recording Film in the PresentEmbodiment”.

ε] Reliability of reproduction information is improved for a case inwhich reproduction signal degradation due to ultraviolet ray orreproduction light irradiation occurs

In the present embodiment, although a technical contrivance is made for“stabilizing an electron structure in a light emitting area”, thereliability of the recording mark 9 formed in a principle of recordingshown in the present embodiment may be principally lowered as comparedwith a local cavity in the recording layer 3-2 generated due to plasticdeformation or gasification (evaporation) of the surface of thetransparent substrate 2-2. As countermeasures against it, in the presentembodiment, advantageous effect that the high density and thereliability of recording information are achieved at the same time incombination with strong error correction capability (novel ECC blockstructure), as described later in “Chapter 7: Description of H Format”and “Chapter 8: Description of B Format”. Further, in the presentembodiment, PRML (Partial Response Maximum Likelihood) technique isemployed as a reproduction method, as described in the section “4-2Description of reproducing circuit in the present embodiment”, the highdensity and the reliability of recording information are achieved at thesame time in combination with an error correction technique at the timeof ML demodulation.

Among the specific characteristics of the above described presentembodiment, a description has been given with respect to the fact thatitems [α] to [γ] are the contents of technical contrivance newly devisedin the present embodiment in order to achieve “narrow track pitch” and“narrow channel bit length”. In addition, “narrow channel bit length”causes the achievement of “reduction of minimum recording mark length”.The meanings (objects) of the present embodiment relating to theremaining items [δ] and [ε] will be described in detail. At the time ofreproduction in the H format in the present embodiment, a passage speed(line speed) of a focusing spot of light passing through the recordinglayer 3-2 is set to 6.61 m/s, and the line speed in the B format is setin the range of 5.0 m/s to 10.2 m/s.

In any case, the line speed at the time of reproduction in the presentembodiment is equal to or greater than 5 m/s. As shown in FIG. 14, astart position of a data lead-in area DTLDI in the H format is 47.6 mmin diameter. In view of the B format as well, user data is recorded inlocation equal to or greater than 45 mm in diameter. An inner peripheryof 45 mm in diameter is 0.141 m, and thus, the rotation frequency of aninformation storage medium when this position is reproduced at a linespeed of 5 m/s is obtained as 35.4 rotations/second. Video imageinformation such as TV program is provided as one of the methodsutilizing a write-once type information storing medium according to thepresent embodiment. For example, when a user presses “pause (temporarystop) button” at the reproduction of the user's recorded video image, areproduction focusing spot stays on a track of its paused position. Whenthe spot stops on the track of the paused position, the user can startreproduction at the paused position immediately after a “reproductionstart button” has been pressed. For example, after the user has presseda “pause (temporary stop) button”, in the case where a customer visitsthe user's home immediately after the user has gone to toilet, there isa case in which the pause button is left to have been pressed for onehour while the user meets the customer. The write-once type informationstorage medium makes 35.4×60×60=130,000 rotations for one hour, and thefocusing spot traces on the same track during this period (130,000repetitive playbacks). If the recording layer 3-2 is degraded due torepetitive playback and video image information cannot be reproducedafter this period, the user coming back one hour later cannot see anyportion of video image, and thus, gets angry, and in the worst case,there is a danger that the problem may be taken to court. Therefore, aminimum condition that, if the recorded video image information is notdestroyed even if such a pausing is left for one hour or longer (even ifcontinuous playback in the same track occurs), no video image data isdestroyed, requires to guarantee that at least 100,000 repetitiveplayback occurs, no reproduction degradation occurs. There is a rarecase in which a user repeats one-hour pausing (repetitive playback) 10times with respect to the same location in a general use condition.Therefore, when it is guaranteed that the write-once type informationstorage medium according to the present embodiment desirably makes1,000,000 repetitive playbacks, no problem occurs with use by thegeneral user, and it is considered sufficient to set to about 1,000,000times the upper limit value of the repetitive playback count as long asthe recording layer 3-2 is not degraded. If the upper limit value of therepetitive playback count is set to a value which significantly exceeds1,000,000 times, there occurs inconvenience that “recording sensitivityis lowered” or “medium price increases”.

In the case where the upper limit value of the above repetitivereproduction count is guaranteed, a reproduction power value becomes animportant factor. In the present embodiment, recording power is definedin a range set in formulas (8) to (13). It is said that a semiconductorlaser beam is featured in that continuous light irradiation is notstable in a value equal to or smaller than 1/80 of the maximum usepower. Because the power, which is 1/80 of the maximum use power, is inlocation in which light irradiation is just started (mode initiation isstarted), mode hopping is likely to occur. Therefore, at this lightirradiation power, the light reflected in the light reflection layer 4-2of the information storage medium comes back to a semiconductor laserlight source, there occurs a “return light noise” featured in that thelight emission amount always changes. Accordingly, in the presentembodiment, the values of the reproduction power is set below around thevalue which is 1/80 of the value described at the right side of formula(12) or formula (13):

[Optical reproduction power]>0.19×(0.65/NA)²×(V/6.6)   (B-1)

[Optical reproduction power]>0.19×(0.65/NA)²×(V/6.6)^(1.2)   (B-2)

In addition, the value of the optimal reproduction power is restrictedby a dynamic range of a power monitoring optical detector. Although notshown in an information recording/reproducing unit 141 of FIG. 8, arecording/reproducing optical head exists. This optical headincorporates an optical detector which monitors a light emission amountof a semiconductor laser light source. In the present embodiment, inorder to improve light irradiation precision of the reproduction powerat the time of reproduction, this optical detector detects a lightemission amount and applies a feedback to an amount of a current to besupplied to the semiconductor laser light source at the time of lightirradiation. In order to lower a price of the optical head, it isnecessary to use a very inexpensive optical detector. A commerciallyavailable, inexpensive optical detector is often molded with a resin (anoptical detecting unit is surrounded).

As disclosed in “Chapter 0: Description of Relationship between UseWavelength and the Present Embodiment”, 530 nm or less (in particular,455 nm or less) is used as a light source wavelength in the presentembodiment. In the case of this wavelength area, a resin with which theoptical detecting unit is molded (mainly, epoxy resin) causes such adegradation that occurs when ultraviolet ray has been irradiated if thewavelength light is irradiated (such as dark yellow discoloring oroccurrence of cracks (fine white stripes)) and the optical detectioncharacteristics are impaired. In particular, in the case of thewrite-once type information storage medium shown in the presentembodiment, a mold resin degradation is likely to occur because thestorage medium has a pre-groove area 11 as shown in FIGS. 7A, 7B and 7C.As a focus blurring detection system of an optical head, in order toremove adverse effect due to the diffraction light from this pre-groovearea 11, there is most often employed a “knife-edge technique” ofallocating an optical detector at an image forming position relevant tothe information storage medium (image forming magnification M is inorder of 3 times to 10 times). When the optical detector is arranged atthe image forming position, high optical density is irradiated onto amold resin because light beams are focused on the optical detector, andresin degradation due to this light irradiation is likely to occur. Thismold resin characteristic degradation mainly occurs due to a photon mode(optical action), and however, it is possible to predict an upper limitvalue of an allowable irradiation amount in comparison with a lightemission amount in a thermal mode (thermal excitation). Assuming theworst case, let us assume an optical system in which an optical detectoris arranged at an image forming position as an optical head.

From the contents described in “(1) Condition for thickness Dg ofrecording layer 3-2” in “3-2-A] Range requiring application of techniqueaccording to the present embodiment”, when an optimal characteristicchange (thermal mode) occurs in the recording layer 3-2 at the time ofrecording in the present embodiment, it is considered that a temperaturetemporarily rises in the range of 80° C. to 150° C. in the recordinglayer 3-2. In view of a room temperature of about 15° C., a temperaturedifference ΔT_(write) ranges from 65° C. to 135° C. Pulse lightemissions occur at the time of recording, and continuous light emissionsoccur at the time of reproduction. At the time of reproduction, thetemperature rises in the recording layer 3-2 and a temperaturedifference AT_(read) occurs. When an image forming magnification of adetecting system in the optical head is M, the optical density of thedetected light focused on the optical detector is obtained as 1/M² ofthe optical density of convergence light irradiated on the recordinglayer 3-2, and thus, a temperature rise amount on the optical detectorat the time of reproduction is obtained as ΔT_(read)/M² which is a roughestimate. In view of the fact that an upper limit value of opticaldensity, which can be irradiated on the optical detector, is convertedby the temperature rise amount, it is considered that the upper limitvalue is in order of ΔT_(read)/M²≦1° C. The image foaming magnificationof the detecting system in the optical head M is in order of 3 times to10 times in general, if the magnification M²≅10 is tentativelyestimated, it is necessary to set reproduction power so as to obtain:

ΔT _(read) /ΔT _(write)≦20   (B-3)

Assuming that a duty ratio of recording pulses at the time of recordingis estimated as 50%, the following is required:

[Optimal reproduction power]≦[Optimal recording power]/10   (B-4)

Therefore, in view of formulas (8) to (13) described later and the aboveformula (B-4), optimal reproduction power is assigned as follows:

[Optimal reproduction power]<3×(0.65/NA)²×(V/6.6)   (B-5)

[Optimal reproduction power]<3×(0.65/NA)²×(V/6.6)^(1/2)   (B-6)

[Optimal reproduction power]<2×(0.65/NA)²×(V/6.6)   (B-7)

[Optimal reproduction power]<2×(0.65/NA)²×(V/6.6)^(1/2)   (B-8)

[Optimal reproduction power]<1.5×(0.65/NA)²×(V/6.6)   (B-9)

[Optimal reproduction power]<1.5×(0.65/NA)²×(V/6.6)^(1/2)   (B-10)

(Refer to “3-2-E] Basic characteristics relating to thicknessdistribution of recording layer in the present embodiment for definitionof parameters”.) For example, when NA=0.65 and V=6.6 m/s, the followingis obtained:

[Optimal reproduction power]<3 mW,

[Optimal reproduction power]<2 mW, or

[Optimal reproduction power]<1.5 mW.

In reality, the optical detector is fixed as compared with the fact theinformation storage medium rotates and relatively moves, and thus, inconsideration of this fact, it is necessary to further set the optimalreproduction power to be in order of ⅓ or less of the value obtained inthe above formula. In the information recording/reproducing apparatusaccording to the present embodiment, a value of the reproduction poweris set to 0.4 mW.

3-2-C] Ideal recording film structure in which a principle of recordingshown in the present embodiment is easily generated

A description will be given with respect to a method for “setting anenvironment” (recording film structure or shape) in which the aboveprinciple of recording is easily generated in the present embodiment.

As an environment in which an optical characteristic change inside ofthe above described recording layer 3-2 is likely to occur, the presentembodiment is featured in that a technical contrivance is carried out inrecording film structure or shape such as:

“in an area for forming the recording mark 9, a critical temperature atwhich an optical characteristic change is likely to occur is exceeded,and at a center part of the recording mark 9, a gasification(evaporation) temperature is not exceeded, and a surface of atransparent substrate 2-2 in the vicinity of the center part of therecording mark 9 does not exceed a thermal temperature”

The specific contents relating to the above description will bedescribed with reference to FIGS. 6A, 6B and 6C. In FIGS. 6A, 6B and 6C,the open (blank) arrow indicates an optical path of an irradiation laserlight beam 7, and the arrow of the dashed line indicates a thermal flow.A recording film structure shown in FIG. 6A indicates an environment inwhich an optical characteristic change inside of a recording layer 3-2corresponding to the present embodiment is most likely to occur. Thatis, in FIG. 6A, the recording layer 3-2 consisting of an organic dyerecording material has uniform thickness anywhere in the range shown informula (3) or formula (4) (where the thickness is sufficiently large),and receives irradiation of the laser light beam 7 in a directionvertical to the recording layer 3-2. As described in detail in “6-1)light reflection layer (material and thickness)”, a silver alloy is usedas a material for a light reflection layer 4-2 in the presentembodiment. A material including a metal with high light reflectionfactor, in general, has high thermal conductivity and heat radiationcharacteristics without being limited to the silver alloy. Therefore,although a temperature of the recording layer 3-2 is risen by absorbingthe energy of the irradiated laser light beam 7, a heat is radiatedtoward the light reflection layer 4-2 having heat radiationcharacteristics. Although a recording film shown in FIG. 6A is formedanywhere in a uniform shape, a comparatively uniform temperature riseoccurs inside of the recording layer 3-2, and a temperature differenceat points α, β, and γ at the center part is comparatively small.Therefore, when the recording mark 9 is formed, when a criticaltemperature at which an optical characteristic change at the points αand β occurs is exceeded, a gasification (evaporation) temperature isnot exceeded at the point α of the center part; and a surface of atransparent substrate (not shown) which exists at a position which isthe closest to the point α of the center part does not exceed a thermaldeformation temperature.

In comparison, as shown in FIG. 6B, a step is provided partly of therecording film 3-2. At the points δ and ε, the radiation of the laserlight beam 7 is subjected in a direction oblique to a direction in whichthe recording layer 3-2 is arrayed, and thus, an irradiation amount ofthe laser light beam 7 per a unit area is relatively lowered as comparedwith the point α of the center part. As a result, a temperature riseamount in the recording layer 3-2 at the points δ and ε is lowered. Atthe points δ and ε as well, thermal radiation toward the lightreflection layer 4-2 occurs, and thus, the arrival temperature at thepoints δ and ε is sufficiently lowered as compared with the point α ofthe center part. Therefore, a heat flows from the point β to the point αand a heat flows from the point α to the point β, and thus, atemperature difference at the points β and γ relevant to the point α ofthe center part becomes very small. At the time of recording, atemperature rise amount at the points β and γ is low, and a criticaltemperature at which an optical characteristic change occurs is hardlyexceeded at the points β and α. As countermeasures against it, in orderto produce an optical characteristic change occurs at the points β and γ(in order to produce a critical temperature or more), it is necessary toincrease an exposure amount (recording power) of the laser light beam 7.In the recording film structure shown in FIG. 6B, a temperaturedifference at the point α of the center part relevant to the points βand γ is very large. Thus, when a current temperature has risen at atemperature at which an optical characteristic change occurs at thepoints β and γ, a gasification (evaporation) temperature is exceeded atthe point α of the center part or the surface of a transparent substrate(not shown) in the vicinity of the point α of the center part hardlyexceeds a thermal deformation temperature.

In addition, even if the surface of the recording layer 3-2 at the sideat which irradiation of the laser light beam 7 is subjected is verticalto the irradiation direction of the laser light beam 7 anywhere, in thecase where the thickness of the recording layer 3-2 changes depending ona location, there is provided a structure in which an opticalcharacteristic change inside of the recording layer 3-2 according to thepresent embodiment hardly occurs. For example, as shown in FIG. 6C, letus consider a case in which the thickness D1 of a peripheral part issignificantly small with respect to the thickness Dg of the recordinglayer 3-2 at the point α of the center part (for example, formula (2) orformula (4) is not satisfied). Even at the point α of the center part,although heat radiation toward the light reflection layer 4-2 occurs,the thickness Dg of the recording layer 3-2 is sufficiently large, thusmaking it possible to achieve heat accumulation and to achieve a hightemperature. In comparison, at the points ξ and η at which the thicknessD1 is significantly small, a heat is radiated toward the lightreflection layer 4-2 without carrying out heat accumulation, and thus, atemperature rise amount is small. As a result, heat radiation towardpoints β, δ, and ξ in order and heat radiation toward points γ, ε, and ηin order occurs as well as heat radiation toward the light reflectionlayer 4-2, and thus, as in FIG. 6B, a temperature difference at thepoint α of the center part relevant to points β and γ becomes verylarge. When an exposure amount of the laser light beam 7 (recordingpower) is increased in order to produce an optical characteristic changeat the points β and γ (in order to produce a critical temperature ormore), the gasification (evaporation) temperature at the point α of thecenter part is exceeded or the surface of the transparent substrate (notshown) in the vicinity of the point α of the center part easily exceedsa thermal deformation temperature.

Based on the contents described above, referring to FIGS. 7A, 7B and 7C,a description will be given with respect to: the contents of a technicalcontrivance in the present embodiment relating to the pre-grooveshape/dimensions for providing “setting of environment (structure orshape of a recording film)” in which a principle of recording accordingto the present embodiment is likely to occur; and the contents of atechnical contrivance in the present embodiment relating to a thicknessdistribution of the recording layer. FIG. 7A shows a recording filmstructure in a conventional write-once type information storage mediumsuch as CD-R or DVD-R; and FIGS. 7B and 7C each show a recording filmstructure in the present embodiment. In the invention, as shown in FIGS.7A, 7B and 7C, a recording mark 9 is formed in a pre-groove area 11.

3-2-D] Basic characteristics relating to pre-groove shape/dimensions inthe present embodiment

As shown in FIG. 7A, there have been many cases in which a pre-groovearea 11 is formed in a “V-groove” shape in a conventional write-oncetype information storage medium such as CD-R or DVD-R. In the case ofthis structure, as described in FIG. 6B, the energy absorptionefficiency of the laser light beam 7 is low, and the temperaturedistribution non-uniformity in the recording layer 3-2 becomes verylarge. The present embodiment is featured in that, in order to makeclose to an ideal state of FIG. 6A, a planar shape orthogonal to atraveling direction of the incident laser light beam 7 is provided inthe pre-groove area 11 at the side of at least the “transparentsubstrate 2-2”. As described with reference to FIG. 6A, it is desirablethat this planar area be as wide as possible. Therefore, the presentembodiment is featured in that the planar area is provided in thepre-groove area 11 and the width Wg of the pre-groove area 11 is widerthan the width W1 of a land area (Wg>W1). In this description, the widthWg of the pre-groove area and the width W1 of the land area are definedas their respective widths at a position at which there crosses a planehaving an intermediate height between a height at a planar position ofthe pre-groove area and a height at a position at which the land areabecomes the highest and an oblique surface in the pre-groove.

A discussion has been made using thermal analysis, data has beenrecorded in a write-once type information storage medium actuallyproduced as a prototype, substrate deformation observation due to asectional SEM (scanning type electronic microscope) image at theposition of the recording mark 9 has been made, and observation of thepresence or absence of a cavity generated due to gasification(evaporation) in the recording layer 3-2 has been repeated. As a result,it is found that advantageous effect is attained by widening the widthWg of the pre-groove area more significantly than the width W1 of theland area. Further, a ratio of the pre-groove area width Wg and the landarea width W1 is Wg:W1=6:4, and desirably, is greater than Wg:W1=7:3,whereby it is considered that a local optical characteristic change inthe recording layer 3-2 is likely to occur while the change is morestable at the time of recording. As described above, when a differencebetween the pre-groove area width Wg and the land area width W1 isincreased, a flat surface is eliminated from the top of the land area12, as shown in FIG. 7C. In the conventional DVD-R disc, a pre-pit (landpre-pit: not shown) is formed in the land area 12, and a format forrecording address information or the like in advance is realized here.Therefore, it is conditionally mandatory to form a flat area in the landarea 12. As a result, there has been a case in which the pre-groove area11 is formed in the “V-groove” shape. In addition, in the conventionalCD-R disc, a wobble signal has been recorded in the pre-groove area 11by means of frequency modulation. In a frequency modulation system inthe conventional CD-R disc, slot gaps (a detailed description of eachformat is given in detail) are not constant, and phase adjustment at thetime of wobble signal detection (PLL: synchronization of PLL (Phase LockLoop)) has been comparatively difficult. Thus, a wall face of thepre-groove area 11 is concentrated (made close to the V-groove) in thevicinity of a center at which the intensity of a reproducing focusingspot is the highest and a wobble amplitude amount is increased, wherebythe wobble signal detection precision has been guaranteed. As shown inFIGS. 7B and 7C, after the flat area in the pre-groove area 11 in thepresent embodiment has been widened, when the oblique surface of thepre-groove area 11 is shifted to the outside relatively than a centerposition of the reproducing focusing spot, a wobble detection signal ishardly obtained. The present embodiment is featured in that the width Wgof the pre-groove area described above is widened and the H formatutilizing PSK (Phase Shift Keying) in which slot gaps at wobbledetection is always fixedly maintained or the B format utilizing FSK(Frequency Shift Keying) or STW (Saw Tooth Wobble) are combined, wherebystable recording characteristics are guaranteed (suitable to high speedrecording or layering) at low recording power and stable wobble signaldetection characteristics are guaranteed. In particular, in the Hformat, in addition to the above combination, “a ratio of a wobblemodulation is lowered more significantly than that of a non-modulationarea”, thereby facilitating synchronization at the time of wobble signaldetection more significantly, and further, stabilizing wobble signaldetection characteristics more significantly.

3-2-E] Basic characteristics relating to thickness distribution ofrecording layer 3-2 in the present embodiment

In the present description, as shown in FIGS. 7B and 7C, the thicknessin a portion at which the recording layer 3-2 in the land area 12 is thethickest is defined as recording layer thickness D1 in the land area 12;and a portion at which the recording layer 3-2 in the pre-groove area 11is the thickest is defined as recording layer thickness Dg in thepre-groove area. As has been described with reference to FIG. 6C, therecording layer thickness D1 in the land area is relatively increased,whereby a local optical characteristic change in the recording layer isstably likely to occur at the time of recording.

In the same manner as that described above, a discussion has been madeusing thermal analysis, data has been recorded in a write-once typeinformation storage medium actually produced as a prototype, substratedeformation observation and observation of the presence or absence of acavity generated due to gasification (evaporation) in the recordinglayer 3-2 by a sectional SEM (scanning type electronic microscope) imageat the position of the recording mark 9 have been made. As a result, ithas been found necessary to set a ratio between the recording layerthickness Dg in the pre-groove area and the recording layer thickness D1in the land area to be equal to or smaller than Dg:D1=4:1. Further,Dg:D1=3:1 is set, and desirably, Dg:D1=2:1 is set, thereby making itpossible to guarantee stability of a principle of recording in thepresent embodiment.

3-3) Recording characteristics common to organic dye recording film inthe present embodiment

As one of “3-2-B] basic characteristics common to an organic dyerecording material in the present embodiment”, the present embodiment isfeatured by recording power control, as described in item [γ].

The formation of the recording mark 9 due to a local opticalcharacteristic change in the recording layer 3-2 occurs at atemperature, which is much lower than a plastic deformation temperatureof the conventional transparent substrate 2-2, at a thermaldecomposition temperature in the recording layer 3-2, or a gasification(evaporation) temperature. Thus, an upper limit value of recording poweris restricted so as not ensure that the transparent substrate 2-2locally exceeds a plastic deformation temperature at the time ofrecording or a thermal decomposition temperature or a gasification(evaporation) temperature is locally exceeded in the recording layer3-2.

In parallel to discussion using thermal analysis, by using an apparatusdescribed later in “4-1) Description of structure and characteristics ofreproducing apparatus or recording/reproducing apparatus in the presentembodiment” and by using a recording condition described later in “4-3)Description of recording condition in the present embodiment”, there hasbeen made a demonstration of a value of optimal power in the case whererecording has been carried out in a principle of recording shown in thepresent embodiment. A numerical aperture (NA) value of an objective lensin the recording/reproducing apparatus used in a demonstration test hasbeen 0.65, and a line speed at the time of recording has been 6.61 m/s.As a value of recording power (Peak Power) defined later in “4-3)Description of recording condition in the present embodiment”, it hasbeen found that:

Gasification (evaporation) occurs with most of an organic dye recordingmaterial at 30 mW, and a cavity occurs in a recording mark;

A temperature of the transparent substrate 2-2 at a position in thevicinity of the recording layer 3-2 significantly exceeds a glasstransition temperature;

A temperature of the transparent substrate 2-2 at a position in thevicinity of the recording layer 3-2 reaches a plastic deformationtemperature (glass transition temperature) at 20 mW;

15 mW or less is desirable in consideration of a margin such as surfacepre-warping or recording power change of an information storage medium.

The “recording power” described above denotes a sum of exposure amountirradiated to the recording layer 3-2. The optical energy density at acenter part of a focusing spot and at a portion at which the opticalintensity density is the highest is obtained as parameters targeted fordiscussion in the present embodiment. The focusing spot size isinversely proportional to the NA value, and thus, the optical energydensity at the center part of the focusing spot increases in proportionto a square of the NA value. Therefore, the current value can beconverted to a value of optimal recording power in the B formatdescribed later or another format (another NA value) (D3) by using arelational formula below:

[Recording power applicable to different NA values]=[Recording powerwhen NA=0.65]×0.65² /NA ²   (5)

Further, optimal recording power changes depending on a line speed V inphase change type recording material. In general, it is said thatoptimal recording power changes in proportion to a ½ square of a linespeed V in phase change type recording material, and changes inproportion to a line speed V in organic dye recording material.Therefore, a conversion formula of optimal recording power considering aline speed V, obtained by extending formula (5), is obtained as follows:

[General recording power]=[Recording power when NA=0.65; 6.6m/s]×(0.65/NA)²×(V/6.6)   (6), or

[General recording power]=[Recording power when NA=0.65; 6.6m/s]×(0.65/NA)²×(V/6.6)^(1/2)   (7)

When the above discussion result is summarized, as recording power forguaranteeing a principle of recording shown in the present embodiment,it is desirable to set an upper limit value such as:

[Optimal recording power]<30×(0.65/NA) ²×(V/6.6)   (8)

[Optimal recording power]<30×(0.65/NA)²×(V/6.6)^(1/2)   (9)

[Optimal recording power]<20×(0.65/NA)²×(V/6.6)   (10)

[Optimal recording power]<20×(0.65/NA)²×(V/6.6)^(1/2)   (11)

[Optimal recording power]<15×(0.65/NA)²×(V/6.6)   (12)

[Optimal recording power]<15×(0.65/NA)²×(V/6.6)^(1/2)   (13)

From among the above formulas, a condition for formula (8) or formula(9) is obtained as a mandatory condition; a target condition for formula(10) or formula (11) is obtained; and a condition for formula (12) orformula (13) is obtained as a desirable condition.

3-4) Description of characteristics relating to “H-L” recording film inthe present embodiment

A recording film having characteristics that a light reflection amountin a recording mark 9 is lower than that in an unrecorded area isreferred to as an “H-L” recording film. In contrast, a recording film inwhich the above light reflection amount is high is referred to as an“L-H” recording film. Among them, with respect to the “H-L” recordingfilm, the present embodiment is featured in that:

1) an upper limit value is provided at a ratio of absorbance at areproduction wavelength relevant to absorbance at a λ_(max write)position of light absorption spectra; and

2) a light absorption spectra profile is changed to form a recordingmark.

In the H format in the present embodiment, as a modulation system, thereis employed ETM (Eight to Twelve: 8-bit data code is converted to12-channel bit) and RLL (1, 10) (Among a code train after modulated, aminimum inversion length relevant to a 12-channel bit length T is 2T,and a maximum inversion length is 11T). Where performance evaluation ofa reproduction circuit described later in “4-2) Description ofreproducing circuit in the present embodiment) is carried out, in orderto stably carry out reproduction by the reproducing circuit, it has beenfound necessary to meet that a ratio of [a differential valueI₁₁≡I_(11H)−I_(11L), where I_(11H) is a reproduction signal amount froman unrecorded area having a sufficiently long length (11T) and I_(11L)is a reproduction signal amount from a recording mark having thesufficiently long length (11T) to [I_(11H)] is:

I ₁₁ /I _(11H)≧0.4   (20) or preferably,

I ₁₁ /I _(11H)>0.2   (21)

In the present embodiment, a PRML (partial response maximum likelihood)method is utilized at the time of signal reproduction recorded at highdensity. In order to precisely carry out detection in accordance with aPRML technique, the linearity of a reproduction signal is requested.

As a method for selecting an organic dye material suitable to a specific“H-L” recording layer, there is selected an organic dye material forwhich, in the present embodiment, based on an optical film design, arefractive factor range in an unrecorded state is n₃₂=1.3 to 2.0; theabsorption coefficient range is k₃₂=0.1 to 0.2, desirably n₃₂=1.7 to1.9; the absorption coefficient range is k₃₂=0.15 to 0.17, and a seriesof conditions described above are met.

In the “H-L” recording film, in light absorption spectra in anunrecorded area, although a wavelength of λ_(max) write is shorter thana wavelength of reproduction light or recording/reproducing light (forexample, 405 nm), the wavelength of λ_(max write) may be longer than awavelength of reproduction light or recording/reproducing light (forexample, 405 nm), without being limited thereto.

In odder to meet the above formula (22) or formula (23), the thicknessDg of the recording layer 3-2 is influenced. For example, if thethickness Dg of the recording layer 3-2 significantly exceeds anallowable value, optical characteristics of only a part coming intocontact with the transparent substrate 2-2 in the recording layer 3-2are changed as a state that follows forming of the recording mark 9,whereby the optical characteristics of a portion coming into contactwith the light reflection layer 4-2 adjacent to its location areobtained as a value equal to that in the unrecorded area. As a result, areproduction light amount change is lowered, and a value of I₃ informula (22) or formula (23) is reduced, and a condition for formula(22) or formula (23) cannot be met. Therefore, in order to meet formula(22), as shown in FIGS. 7B and 7C, it is necessary to make a change tothe optical characteristics of a portion which comes into contact withthe light reflection layer 4-2 in the recording mark 9. Further, if thethickness Dg of the recording layer 3-2 significantly exceeds anallowable value, a temperature gradient occurs in the thicknessdirection in the recording layer 3-2 when the recording mark is formed.Then, before reaching the optical characteristic change temperature at aportion coming into contact with the light reflection layer 4-2 in therecording layer 3-2, a gasification (evaporation) temperature of aportion coming into contact with the transparent substrate 2-2 isexceeded or a thermal deformation temperature is exceeded in thetransparent substrate 2-2. For the above reason, in the presentembodiment, in order to meet formula (22), the thickness Dg of therecording layer 3-2 is set to “3T” or less based on the discussion ofthermal analysis; and a condition meeting formula (23) is such that thethickness Dg of the recording layer 3-2 is set to “3×3T” or less.Basically, in the case where the thickness Dg of the recording layer 3-2is equal to or smaller than “3T”, although formula (22) can be met, thethickness may be set to “T” or less in consideration of effect of a tiltdue to a facial motion or warping of the write-once type informationstorage medium or a margin relevant to a focal blurring. Inconsideration of a result obtained by formulas (1) and (2) describedpreviously, the thickness Dg of the recording layer 3-2 in the presentembodiment is set in the range assigned in a required minimum conditionthat:

9T≧Dg≧λ/8n ₃₂   (27)

and in a desired condition that:

3T≧Dg≧λ/4n ₃₂   (28)

Without being limited thereto, the severest condition can be defined as:

T≧Dg≧λ/4n ₃₂   (29)

As described later, a value of the channel bit length T is 102 nm in theH format, and is 69 nm to 80 nm in the B format. Thus, a value of 3T is306 nm in the H format and is 207 nm to 240 nm in the B format. A valueof 9T is 918 nm in the H format and is 621 nm to 720 nm in the B format.Here, although an “H-L” recording film has been described, theconditions for formulas (27) to (29) can be applied to an “L-H”recording film without being limited thereto.

Chapter 4: Description of Reproducing Apparatus or Recording/ReproducingApparatus and Recording Condition/Reproducing Circuit

4-1) Description of structure and characteristics of reproducingapparatus or recording/reproducing apparatus in the present embodiment

FIG. 8 shows an illustration of a structure in an embodiment of aninformation recording/reproducing apparatus. In FIG. 8, an upper side ofa control unit 143 mainly indicates an information recording controlsystem for an information storage medium. In the embodiment of theinformation reproducing apparatus, a structure excluding the informationrecording control system in FIG. 8 corresponds to the above structure.In FIG. 8, the arrow drawn by the thick solid line indicates a flow ofmain information which designates a reproduction signal or a recordingsignal; the arrow of the thin solid line denotes a flow of information;the arrow of the one-dotted chain line denotes a reference clock line;and the arrow of the thin dashed line denotes a command indicatingdirection.

An optical head (not shown) is arranged in an informationrecording/reproducing unit 141 shown in FIG. 8. In the presentembodiment, although a wavelength of a light source (semiconductorlaser) used in the optical head is 405 nm, the present embodiment is notlimited thereto, and there can be used a light source having a usewavelength equal to or shorter than 620 nm or 530 nm or a light sourceranging from 355 nm to 455 nm, as described previously. In addition, twoobjective lenses used to focus the light beam having the abovewavelength onto the information storage medium may be incorporated inthe optical head. In the case where a recording/reproducing operation iscarried out with respect to an information storage medium in the Hformat, an objective lens having a NA value of 0.65 is used. A structureis provided such that, in the case where a recording/reproducingoperation is carried out with respect to an information storage mediumin the B format, an objective lens having NA=0.85 is used. As anintensity distribution of incident light immediately before the light isincident to an objective lens, the relative intensity at the peripheryof the objective lens (at the boundary position of an aperture) when thecenter intensity is set to “1” is referred to as “RIM Intensity”. Avalue of the RIM intensity in the H format is set in the range of 55% to70%. At this time, a wave surface aberration amount in the optical headis optically designed so as to be 0.33λ (0.33λ or less) with respect toa use wavelength λ.

In the present embodiment, a partial response maximum likelihood (PRML)is used for information reproduction to achieve high density of aninformation storage medium (point [A]). As a result of a variety oftests, when PR(1, 2, 2, 2, 1) is used as a PR class to be used, linedensity can be increased and the reliability of a reproduction signalcan be improved (i.e., demodulation reliability can be improved) when aservo correction error such as a focal blurring or a track shift hasoccurred. Thus, in the present embodiment, PR(1, 2, 2, 2, 1) is employed(point [A1]). In the present embodiment, a channel bit pattern aftermodulated is recorded in an information storage medium in accordancewith a (d, k; m, n) modulation rule (In the above described method, thisdenotes RLL(d, k) of m/n modulation).

Specifically, ETM (Eight to Twelve Modulation) for converting 8-bit datato a 12-channel bit (m=8, n=12) is employed as a modulation system, anda condition of RLL (1, 10) in which a minimum value having continuous“0”s is defined as d=1, and a maximum value is defined as k=10 as a runlength limited RLL restriction for apply limitation to a length thatfollows “0” in the channel bit pattern after modulated must be met. Inthe present embodiment, in order to achieve high density of aninformation storage medium, a channel bit gap is reduced to the minimum.As a result, for example, after a pattern “101010101010101010101010”which is a repetition of a pattern of d=1 has been recorded in theinformation storage medium, in the case where the data is reproduced inan information recording/reproducing unit 141, the data is close to ashutdown frequency having MTF characteristics of a reproducing opticalsystem, and thus, a signal amplitude of a reproduced raw signal isformed in a shape almost hidden by noise. Therefore, a partial responsemaximum likelihood (PRML) technique is used as a method for thusreproducing a recording mark or a pit, which has been dense up to thevicinity of a limit of the MTF characteristics (shutdown frequency).That is, a signal reproduced from the information recording/reproducingunit 141 receives reproducing waveform correction by a PR equalizercircuit 130.

A signal having passed through the PR equalizer circuit 130 is sampledby converting a signal after passing through the PR equalizer circuit130 to a digital amount in accordance with a timing of a reference clock198 sent from a reference clock generating circuit 160; the sampledsignal is converted to a digital data by an AD converter 169; and aViterbi decoding process is carried out in a Viterbi decoder 156. Thedata after Viterbi-decoded is processed as data, which is completelysimilar to binary data at a conventional slice level. In the case wherethe PRML technique has been employed, if a sampling timing obtained bythe AD converter 169 is shifted, an error rate of the data after Viterbidecoded increases. Therefore, in order to enhance precision of thesampling timing, the information reproducing apparatus or informationrecording/reproducing apparatus according to the present embodiment hasanother sampling timing sampling circuit in particular (combination ofSchmidt trigger binarizing circuit 155 and PLL circuit 174). ThisSchmidt trigger circuit 155 has a specific value (forward directionvoltage value of diode in actuality) at a slice reference level forbinarizing, and is featured in that binarizing is provide only when thespecific width has been exceeded. Therefore, for example, as describedabove, in the case where a pattern of “101010101010101010101010” hasbeen input, a signal amplitude is very small, and thus, switching ofbinarizing does not occur. In the case where “1001001001001001001001” orthe like, for example, being a pattern of a rarer fraction than theabove, has been input, an amplitude of a reproducing raw signalincreases, and thus, the polarity switching of a binary signal occurs inaccordance with a timing of “1” by a Schmidt trigger binarizing circuit155. In the present embodiment, an NRZI (Non Return to Zero Invert)technique is employed, and a position of “1” of the above patterncoincides with an edge section (boundary section) of a recording mark ora pit.

A PLL circuit 174 detects a shift in frequency and phase between abinary signal which is an output of this Schmidt trigger binarizingcircuit 155 and a signal of a reference clock 198 sent from a referenceclock generating circuit 160 to change the frequency and phase of theoutput clock of the PLL circuit 174. A reference clock generatingcircuit 160 applies a feedback to (a frequency and a phase) of areference clock 198 so as to lower an error rate after Viterbi decoded,by using an output signal of this PLL circuit 174 and decodingcharacteristic information on a Viterbi decoder 156 and a convergencelength (information on (distance to convergence)) in a path metricmemory in the Viterbi decoder 156, although is not specifically shown).The reference clock 198 generated by this reference clock generatingcircuit 160 is utilized as a reference timing at the time ofreproduction signal processing.

A sync code position sampling unit 145 serves to detect the presence andposition of a sync code, which coexists in an output data train of theViterbi decoder 156 and to sample a start position of the above outputdata. While this start position is defined as a reference, a demodulatorcircuit 152 carries out a demodulating process with respect to datatemporarily stored in a shift resistor circuit 170. In the presentembodiment, the above temporarily stored data is returned to itsoriginal bit pattern with reference to a conversion table recorded in ademodulating conversion table recording unit 154 on 12-channel bit bybit basis. Then, an error correcting process is performed by an ECCdecoding circuit 162, and descrambling is carried out by a descramblingcircuit 159. Address information is recorded in advance by wobblemodulation in a recording type (rewritable type or write-once type)information storage medium according to the present embodiment. A wobblesignal detecting unit 135 reproduces this address information (i.e.,judges the contents of a wobble signal), and supplies informationrequired to provide an access to a desired location to the control unit143.

A description will be given with respect to an information recordingcontrol system provided at the upper side than the control unit 143.After data ID information has been generated from a data ID generatingunit 165 in accordance with a recording position on an informationstorage medium, when copy control information is generated by a CPR_MAIdata generating unit 167, a variety of information on data ID, IED,CPR_MAI, and EDC is added to information to be recorded by a data ID,IED, CPR_MAI, and EDC adding unit 168. After the added information hasbeen descrambled by the descrambling circuit 157, an ECC block is formedby an ECC encoding circuit 161, and the ECC block is converted to achannel bit pattern by a modulating circuit 151. A sync code is added bya sync code generating/adding unit 146, and data is recorded in aninformation storage medium in the information recording/reproducing unit141. At the time of modulation, DSV values after modulated aresequentially calculated by a DSV (Digital Sum Value) calculating unit148, and the serially calculated values are fed back to code conversionafter modulated.

FIG. 9 shows a detailed structure of peripheral portions including thesync code position detector unit 145 shown in FIG. 8. A sync code iscomposed of a sync position detecting code section and a variable codesection having a fixed pattern. From the channel bit pattern output froma Viterbi decoder, a sync position detecting code detector unit 182detects a position of a sync position detecting code section having theabove fixed pattern. Variable code transfer units 183 and 184 sampledata on a variable code which exists before and after the detectedposition, and judge in which sync frame in a sector the sync code ispositioned, the sync code being detected by an identifying unit 185 fordetecting a sync position having the above fixed pattern. Userinformation recorded on an information storage medium is sequentiallytransferred in order of a shift register circuit 170, a demodulationprocessing unit 188 in a demodulator circuit 152, and an ECC decodingcircuit 162.

In the present embodiment, in the H format, the high density of theinformation storage medium is achieved (in particular, line density isimproved) by using the PRML system for reproduction in a data area, adata lead-in area, and a data lead-out area. In addition, compatibilitywith a current DVD is ensured and reproduction stability is ensured byusing a slice level detecting system for reproducing in a system lead-inarea and a system lead-out area. (A detailed description will be givenlater in “Chapter 7: Description of H Format”.)

Chapter 5: Specific Description of Organic Dye Recording Film in thePresent Embodiment

5-1) Description of characteristics relating to “L-H” recording film inthe present embodiment

A description will be given with respect to an “L-H” recording filmhaving characteristics in which a light reflection amount is lowered ina recording mark as compared with that in an unrecorded area. From amongprinciples of recording described in “3-2-B] Basic characteristicscommon to organic dye recording material in the present embodiment”, aprinciple of recording in the case of using this recording film mainlyutilizes any of:

Chromogenic Characteristic Change;

Change of electron structure (electron orbit) relevant to elements whichcontribute to chromogenic phenomenon [discoloring action or the like];and

Array change between molecules, and changes characteristics of lightabsorption spectra. The “L-H” recording film is featured in that thereflection amount range in an unrecorded location and a recordedlocation has been specified in view of characteristics of a read-onlytype information storage medium having a one-sided dual layeredstructure.

FIG. 10 shows reflection factors at a non-recording position and arecorded position in a variety of recording films in the presentembodiment. In the case where an H format has been employed (refer to“Chapter 7: Description of H Format”), a signal appears in a samedirection in an emboss area (such as system leas-in area SYLDI) and arecording mark area (data lead-in area DTLDI, data lead-out area DTLDO,or data area DTA) in the “L-H” recording film while a groove level isdefined as a reference. Similarly, in the “H-L” recording film, while agroove level is defined as a reference, a signal appears in an oppositedirection in an emboss area (such as system lead-in area SYSDI) and arecording mark area (data lead-in area DTLDI, data lead-out area DTLDO,or data area DTA). Utilizing this phenomenon, a detecting circuit designcorresponding to the “L-H” recording film and “H-L” recording film isfacilitated in addition to use for recording film identification betweenthe “L-H” recording film and the “H-L” recording film. In addition, thereproduction signal characteristics obtained from a recording markrecorded on the “L-H” recording film shown in the present embodiment isadjusted to conform to signal characteristics obtained from the “H-L”recording film to meet formulas (20) to (23). In this manner, in thecase of using either one of the “L-H” recording film and the “H-L”recording film, the same signal processor circuit can be used, and thesignal processor circuit can be simplified and reduced in price.

Referring to FIGS. 27A and 27B, a description will be given with respectto another embodiment relevant to an embodiment showing a relationshipin light reflection factor between an “H-L” recording film and an “L-H”recording film shown in FIG. 10.

In the present embodiment, as shown in FIGS. 7B and 7C, the width Wg ofthe pre-groove area 11 is set to be wider than the width W1 of the landarea 12. In this manner, according to the present embodiment, a signallevel (Iot)groove from the pre-groove area 11 is increased when trackingis carried out on the pre-groove area 11 (data lead-in area DTLDI ordata area DTA and inside of data lead-out area DTLDO).

In the present embodiment, a “light reflection factor” is defined byusing a detection signal level detected by using an optical head, asdescribed below.

First, a parallel laser light beam of an incident light quantity I_(O)is irradiated to a specific area free from fine irregularities such aspre-pits or pre-grooves of the information storage medium 1101; areflection light quantity I_(R) of the parallel laser light beamreflected from the information storage medium 1101 is measured; and avalue of Rs=I_(R)/I_(O) is utilized as a reference of the lightreflection factor Rs. In this way, the value measured without using anoptical head is defined as a calibrated light reflection factor Rs.Next, a detection signal level detected by using an optical head in itspredetermined area is defined as reflection light power Ds, and a valueof (Rs/Ds) is utilized as a conversion coefficient for converting into a“light reflection factor” from the detection signal level detected byusing the optical head at each position of the information storagemedium 1101.

According to the present embodiment, a reflection factor of aninformation recording medium is specified so that the light reflectionfactor of the system lead-in area SYLDI of the “H-L” recording filmranges from 16% to 32%.

Further, a ratio (Iot)groove/I11HP of the light reflection quantity(Iot)groove in a unrecorded area in the “H-L” recording film to thereflection factor I11HP in the system lead-in area SYLDI according tothe present embodiment is specified at a high level so as to be includedin the range of 0.5 to 1.0. As shown in FIGS. 7B and 7C, the width Wg ofthe pre-groove area 11 is narrower than the width W1 of the land area12, thereby increasing a level of (Iot)groove. In particular, in the“H-L” recording film, thickness Dg of the recording layer 3-2 isincreased, thereby reducing a step difference quantity Hr between grooveand land areas. In this manner, the level of (Iot)groove is increased sothat a value of (Iot)groove/I11HP is 50% or more. As a result, the lightreflection quantity I11HM from the recording mark recorded in the groovearea 11 can be increased, and the detection signal amplitude from therecording mark on the groove area 11 is increased.

Now, referring to FIGS. 27A and 27B, a description will be given withrespect to a detection signal level in an “L-H” recording film. A laserlight 1117 emitted from a semiconductor laser 1121 is changed to aparallel beam through a collimator lens 1122. The parallel beam ispassed through a beam splitter 1123 and focused onto a pre-groove area1111 of an optical disc 1101 through an objective lens 1128. The lightreflected from the pre-groove area 1111 is incident on the beam splitter1123 through the objective lens 1128. The light reflected by the beamsplitter 1123 is irradiated on an optical sensor 1125 through acondenser lens 1124. The optical sensor 1125 includes optical detectorcells 1125-1 and 1125-2 which output detection signals I1 and I2. Thelight reflection quantity in the system lead-in area SYLDI of the “L-H”recording film is defined by (Rs/Ds)×I11HP as in the “H-L” recordingfilm. In the present embodiment, the light reflection factor in thesystem lead-in area SYLDI of the “L-H” recording film is specified inthe range of 14% to 28%. In the “L-H” recording film, the thicknesses Dgand Dl of the recording film 3-2 in the pre-groove area 11 and the landarea 12 shown in FIGS. 7B and 7C are relatively made small. Thus, thedetection signal level(Iot) groove in an unrecorded area of thepre-groove area 214 when a track loop is ON in an unrecorded area islower than that of the “H-L” recording film. As a result, in the presentembodiment, a ratio (Iot)groove/I11HP of the light reflection quantity(Iot)groove on the pre-groove area 214 at an unrecorded position of thedata lead-in area DTLDI, the data area DTA, or the data lead-out areaDTLDO is set to be lower than that of the “H-L” recording film so as tobe included in the range of 40% to 80%. In the “L-H” recording film, thelight reflection factor in the recording mark increases moresignificantly than the reflection factor of the unrecorded area, andthus, a reproduction signal waveform as shown in FIG. 27B is produced.In FIG. 27B as well, the highest detection signal level I11HM of thereproduction signal from the recording mark is used as the lightreflection quantity, and the reflection factor is specified by(Rs/Ds)×I11HM. In the present embodiment, the reflection factor in the“L-H” recording film ranges from 14% to 28%. According to the presentembodiment, the light reflection range in the system lead-in area SYLDIis specified so as to partially overlap in the “L-H” recording film andthe “H-L” recording film. There exists an overlap portion a of the lightreflection factors between the “H-L” recording film and the “L-H”recording film in the system lead-in area SYLDI. In the presentembodiment, this light reflection range in this area ranges from 16% to28%. The present embodiment uses a method for overlapping the reflectionfactor range between the “H-L” recording film and the “L-H” recordingfilm in this system lead-in area SYLDI in which an overlap portion ofthe reflection factors between the “H-L” recording film and the “L-H”recording film in the system lead-in area SYLDI is produced bycontrolling optical characteristics of each recording layer 3-2.Further, there is provided an overlap portion β of the light reflectionfactor range when a track loop is ON in the data lead-in area DTLDI, thedata DTA, or the data lead-out area DTLDO. In this overlap portion, the(Iot)groove level in an unrecorded area of the “H-L” recording film isset to be higher than a signal level of the detection signal level(Iot)groove in an unrecorded area of the “L-H” recording film, wherebythe overlap portion β between the light reflection factors exists.

Specifically, as shown in FIGS. 7B and 7C, the film thicknesses Dg andDl of the recording layer 3-2 are set to be greater in the “H-L”recording film than in the “L-H” recording film. As a result, a stepdifference Hr in the light reflection layer 4-2 of the “H-L” recordingfilm is smaller than that of the “L-H” recording film. As a result, thedetection signal level (Iot)groove in an unrecorded area of the “H-L”recording film increases. In the present embodiment, the lightreflection factor range when a track loop is ON is coincident betweenthe “H-L” recording film and the “L-H” recording film. In addition, theoverlap portion β of the light reflection factor is maximized betweenthe “H-L” recording film and the “L-H” recording film in the data areaDTA or the like. Further, in the present embodiment, there exists aportion γ at which the light reflection factors overlap each otherbetween the portion α at which the light reflection factors in thesystem lead-in area SYLDI overlap each other and the portion β at whichthe light reflection factors in the data area DTA overlap each other.

In the present embodiment, as shown in FIG. 7B or 7C, the width Wg ofthe pre-groove area 11 is wider than the width W1 of the land area 12,and a detection signal level (Iot)groove from a groove in an unrecordedarea such as the inside of the data area DTA is reduced, therebyincreasing the overlap portion γ of the light reflection factors betweenthe portions α and β.

5-2) Characteristics of Light Absorption Spectra Relating to “L-H”Recording Film in the Present Embodiment

As has been described in “3-4) Description of characteristics relatingto “H-L” recording film in the present embodiment, the relativeabsorbance in an unrecorded area is basically low in the “H-L” recordingfilm, and thus, when reproduction light has been irradiated at the timeof reproduction, there occurs an optical characteristic change generatedby absorbing energy of the reproduction light. Even if an opticalcharacteristic change (update of recording action) has occurred afterthe energy of the reproduction light has been absorbed in a recordingmark having high absorbance, a light reflection factor from therecording mark is lowered. Thus, reproduction signal processing is lessaffected because such a change works in a direction in which anamplitude of a reproduction signal (In₁₁≡I_(11H)−I_(11L)) of thereproduction signal increases.

In contrast, the “L-H” recording film has optical characteristics that“a light reflection factor of an unrecorded portion is lower than thatin a recording mark”. This means that the absorbance of the unrecordedportion is higher than that in the recording mark. Thus, in the “L-H”recording film, signal degradation at the time of reproduction is likelyto occur as compared with the “H-L” recording film. As described in“3-2-B] Basic characteristics common to organic dye recording materialin the invention”, there is a need for improving reliability ofreproduction information in the case where reproduction signaldegradation has occurred due to ultraviolet ray or reproduction lightirradiation”.

As a result of checking the characteristics of an organic dye recordingmaterial in detail, it has been found that a mechanism of absorbing theenergy of reproduction light to cause an optical characteristic changeis substantially analogous to that of an optical characteristic changedue to ultraviolet ray irradiation. As a result, if there is provided astructure of improving durability relevant to ultraviolet rayirradiation in an unrecorded area, signal degradation at the time ofreproduction hardly occurs. Thus, the present embodiment is featured inthat, in the “L-H” recording film, a value of λ_(max) write (maximumabsorption wavelength which is the closest to wavelength of recordinglight) is longer than a wavelength of recording light or reproductionlight (close to 405 nm). In this manner, the absorbance relevant to theultraviolet ray can be reduced, and the durability relevant toultraviolet ray irradiation can be significantly improved. As is evidentfrom FIG. 12, a difference in absorbance between a recorded portion andan unrecorded portion in the vicinity of λ_(max write) is small, and adegree of reproduction signal modulation (signal amplitude) in the casewhere the wavelength light in the vicinity of λ_(max write) is reduced.In view of a wavelength change of a semiconductor laser light source, itis desirable that a sufficiently large degree of reproduction signalmodulation (signal amplitude) be taken in the range of 355 nm to 455 nm.Therefore, in the present embodiment, a design of a recording film 3-2is made so that a wavelength of λ_(max write) exists out of the range of355 nm to 455 nm (i.e., at a longer wavelength than 455 nm).

FIG. 11 shows an example of light absorption spectra in the “L-H”recording film in the present embodiment. As described in “5-1)Description of feature relating to “L-H” recording film, a lower limitvalue β of a light reflection factor at a non-recording portion (“L”section) of the “L-H” recording film is set to 18%, and an upper limitvalue γ is set to 32% in the present embodiment. From 1−0.32=0.68, inorder to meet the above condition, it is possible to intuitivelyunderstand whether or not a value Al₄₀₅ of the absorbance in anunrecorded area at 405 nm should meet:

Al₄₀₅>68%   (36)

Although the light reflection factor at 405 nm of the light reflectionlayer 4-2 in FIGS. 1A and 1B is slightly lowered than 100%, it isassumed that the factor is almost close to 100% for the sake ofsimplification. Therefore, the light reflection factor when absorbanceAl=0 is almost 100%. In FIG. 11, the light reflection factor of thewhole recording film at a wavelength of λ_(max write) is designated byRλ_(max write). At this time, assuming that the light reflection factoris zero (Rλ_(max write)≈0), formula (36) is derived. However, inactuality, the factor is not set to “0”, and thus, it is necessary todrive a severer formula. A severe conditional formula for setting theupper light value γ of the light reflection factor of the non-recordingportion ‘“L” portion) of the “L-H” recording film to 32% is given by:

1−Al ₄₀₅×(1−Rλ _(max write))≦0.32   (37)

In a conventional write-once type information storage medium, only the“H-L” recording film is used, and there is no accumulation ofinformation relating to the “L-H” recording film. However, in the caseof using the present embodiment described later in “5-3) Anion portion:azo metal complex+cation portion: dye” and “5-4) Using “copper” as azometal complex+center metal”, the most severest condition which meetsformula (37) is obtained as:

Al₄₀₅≧80%   (38)

In the case of using an organic dye recording material described laterin the embodiment, when an optical design of a recording film is madeincluding a margin such as a characteristic variation at the time ofmanufacture or a thickness change of the recording layer 3-2, it hasbeen found that a minimum condition which meet the reflection factordescribed in the section “Description of feature relating to “L-H”recording film” in the present embodiment:

Al₄₀₅≧40%   (39)

may be met. Further, by meeting either of:

Al₃₅₅≧40%   (40)

Al₄₅₅≧40%   (41)

it is possible to ensure stable recording characteristics orreproduction characteristics even if a wavelength of a light source ischanged in the range of 355 nm to 405 nm or in the range of 405 nm to455 nm (in the range of 355 nm to 455 nm in the case where both of theformulas are met at the same time).

FIG. 12 shows a light absorption spectrum change after recorded in the“L-H” recording film according to the present embodiment. It isconsidered that a value of a maximum absorption wavelength λI_(max) in arecording mark deviates from a wavelength of λ_(max write), and aninter-molecular array change (for example, an array change between azometal complexes) occurs. Further, it is considered that a discoloringaction (cutting of local electron orbit (local molecular linkdissociation)) occurs in parallel to a location in which both of theabsorbance in location of λl_(max) and the absorbance Al₄₀₅ at 405 nmare lowered and the light absorption spectra spreads itself.

In the “L-H” recording film according to the present embodiment as well,by meeting each of formulas (20), (21), (22), and (23), the same signalprocessor circuit is made available for both of the “L-H” recording filmand the “H-L” recording film, thereby promoting simplification and pricereduction of the signal processor circuit. In formula (20), when:

I ₁₁ /I _(11H)≡(I _(11H I) _(11L))/I _(11H)≧0.4   (42),

is modified,

I_(11H)≧I_(11L)/0.6 (43) is obtained. As described previously, in thepresent embodiment, a lower limit value β of a light reflection factorof an unrecorded portion (“L” portion) of an “L-H” recording film is setto 18%, and this value corresponds to I_(11L). Further, conceptually,the above value corresponds to:

I _(11H)≈1−Ah ₄₀₅×(1−Rλ _(max write))   (44).

Thus, from formulas (43) and (44), the following formula is established:

1−Ah ₄₀₅×(1−Rλ _(max write))≧0.18/0.6   (45)

In comparison between the above formulas (46) and (36), it is found thatthe values of Al₄₀₅ and Ah₄₀₅ may be seemingly set in the vicinity of68% to 70% as values of absorbance. Further, in view of a case in whichthe value of Al₄₀₅ is obtained in the range of formula (39) andperformance stability of a signal processor circuit, a sever conditionis obtained as:

Ah₄₀₅≦0.4   (47)

If possible, it is desirable to meet;

Ah₄₀₅≦0.3   (48)

5-3) Anion Portion: Azo Metal Complex+Cation Portion: Dye

A description will be specifically given with respect to an organic dyematerial in the present embodiment having characteristics described in“5-1) Description of characteristics relating to “L-H” recording film inthe present embodiment”, the present embodiment meeting a conditionshown in “5-2) Characteristics of optical absorption spectra relating to“L-H” recording film” in the present embodiment”. The thickness of therecording layer 3-2 meets the conditions shown in formulas (3), (4),(27), and (28), and is formed by spinner coating (spin coating). Forcomparison, a description will be given by way of example. A crystal ofa “salt” is assembled by “ion coupling” between positively charged“sodium ions” and negatively charged “chloride ions”. Similarly, inpolymers as well, there is a case in which a plurality of polymers arecombined with each other in the form close to “ion coupling”, formingconfiguring an organic dye material. The organic dye recording film 3-2in the present embodiment is composed of a positively charged “cationportion” and a negatively charged “anion portion”. In particular, theabove recording film is technically featured in that: coupling stabilityis improved by utilizing a “dye” having chromogenic characteristics forthe positively charged “cation portion” and utilizing an organic metalcomplex for the negatively charged “anion portion”; and there is met acondition that “δ] an electron structure in a chromogenic area isstabilized, and structural decomposition relevant to ultraviolet ray orreproduction light irradiation hardly occurs” shown in “3-2-B] Basicfeature common to organic dye recording material in the presentembodiment”. Specifically, in the present embodiment, an “azo metalcomplex” whose general structural formula is shown in FIG. 2 is utilizedas an organic metal complex. In the present embodiment which comprises acombination of an anion portion and a cation portion, cobalt or nickelis used as a center metal M of this azo metal complex, thereby enhancingoptical stability. There may be used: scandium, yttrium, titanium,zirconium, hafnium, vanadium, niobium, tantalum, chrome, molybdenum,tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium,rhodium, iridium, palladium, platinum, copper, silver, gold, zinc,cadmium, or mercury and the like without being limited thereto.

In the present embodiment, as a dye used for the cation portion, thereis used any of a cyanine dye whose general structural formula is shownin FIG. 13; a styril dye; and a monomethine cyanine dye.

Although an azo metal complex is used for the anion portion in thepresent embodiment, a formazane metal complex may be used without beinglimited thereto, for example. The organic dye recording materialcomprising the anion portion and cation portion is first powdered. Inthe case of forming the recording layer 3-2, the powdered organic dyerecoding material is dissolved in organic solvent, and spin coating iscarried out on the transparent substrate 2-2. At this time, the organicsolvent to be used includes: a fluorine alcohol based TFP (tetrafluoropropanol) or pentane; hexane; cyclohexane; petroleum ether; ether oranalogous, nitrile or analogous, and any of a nitro compound orsulfur-containing compound or a combination thereof.

Chapter 6: Description Relating to Pre-Groove Shape/Pre-Pit Shape inCoating Type Organic Dye Recording Film and On Light Reflection LayerInterface

6-1) Light Reflection Layer

As described in “Chapter 0: Description of Relationship between UseWavelength and the Present Embodiment”, the present embodiment assumes arange of 355 nm to 455 nm in particular around 405 nm. When the metalmaterials each having a high light reflection factor at this wavelengthbandwidth are arranged in order from the highest light reflectionfactor, Ag is in the order of around 96%; Al is in the order of around80%, and Rh is in the order of around 80%. In a write-one typeinformation storage medium using an organic dye recording material, asshown in FIG. 1B, the reflection light from the light reflection layer4-2 is a standard, and thus, the light reflection layer 4-2 requires ahigh light reflection factor in characteristics. In particular, in thecase of the “H-L” recording film according to the present embodiment,the light reflection factor in an unrecorded area is low. Thus, if thelight reflection factor in the light reflection layer 4-2 simplex islow, in particular, a reproduction signal C/N ratio from a pre-pit(emboss) area is low, lacking the stability at the time of reproduction.Thus, in particular, it is mandatory that the light reflection factor inthe light reflection layer 4-2 simplex is high. Therefore, in thepresent embodiment, in the above wavelength bandwidth, a material mainlymade of Ag (silver) having the highest reflection factor is used. As amaterial for the light reflection layer 4-2, there occurs a problem that“atoms easily move” or “corrosion easily occurs” if silver is usedalone. To solve the first problem, when partial alloying is carried outby adding other atoms, silver atoms hardly move. In the first embodimentin which other atoms are added, the light reflection layer 4-2 is madeof AgNdCu according to the first embodiment. AgNdCu is in a solidsoluble state, and thus, the reflection factor is slightly lowered thana state in which silver is used alone. In the second embodiment in whichother atoms are added, the light reflection layer 4-2 is made of AgPd,and an electric potential is changed, whereby corrosion hardly occurs inan electrochemical manner. If the light reflection layer 4-2 corrodesdue to silver oxidization or the like, the light reflection factor islowered. In an organic dye recording film having a recording filmstructure shown in FIG. 1B, in particular, in the case of an organic dyerecording film shown in “Chapter 3: Description of Characteristics ofOrganic Dye Recording Film in the Present Embodiment”, in particular, alight reflection factor on an interface between the recording layer 3-2and the light reflection later 4-2 is very important. If correctionoccurs on this interface, the light reflection factor is lowered, and anoptical interface shape blurs. In addition, the detection signalcharacteristics from a track shift detection signal (push-pull signal)or a wobble signal and a pre-pit (emboss) area are degraded. Inaddition, in the case where the width Wg of the pre-groove area 11 iswider than the width W1 of the land area, a track shift detection signal(push-pull signal) or a wobble signal is hardly generated, thusincreasing effect of degradation of the light reflection factor on theinterface between the recording layer 3-2 and the light reflection layer4-2 due to corrosion. In order to prevent degradation of the lightreflection factor on this interface, AgBi is used for the lightreflection layer 4-2 as the third embodiment. AgBi forms a very stablephase and prevents degradation of the light reflection factor on theabove interface because a passive coat film is formed on a surface(interface between the recording layer 3-2 and the light reflectionlayer 4-2). That is, if Bi (bismuth) is slightly added to Ag, Bi isisolated from the above interface, the isolated Bi is oxidized. Then, avery fine film (passive coat film) called oxidized bismuth is formed tofunction to preclude internal oxidization. This passive coat film isformed on the interface, and forms a very stable phase. Thus, thedegradation of a light reflection factor does not occur, and thestability of detection signal characteristics from a track shiftdetection signal (push-pull signal) or a wobble signal and a pre-pit(emboss) area is guaranteed over a long period of time. At a wavelengthband ranging from 355 nm to 455 nm, the silver simplex has the highestlight reflection factor, and the light reflection factor is lowered asan additive amount of other atoms is increased. Thus, it is desirablethat an additive amount of Bi atoms in AgBi in the present embodiment beequal to or smaller than 5 at %. The unit of at % used here denotesatomic percent, and indicates that five Bi atoms exist in a total atomnumber 100 of AgBi, for example. When characteristics have beenevaluated by actually producing the passive coat film, it has found thata passive coat film can be produced as long as an additive amount of Biatoms is equal to or greater than 0.5 at %. Based on a result of thisevaluation, an additive amount of Bi atoms in the light reflection layer4-2 in the present embodiment is defined as 1 at %. In this thirdembodiment, only one atom Bi is added, and an additive amount of atomscan be reduced as compared with AgNdCu according to the first embodiment(a case in which two types of atoms Nd and Cu is added in Ag), and AgBican increase the light reflection factor more significantly than AgNdCu.As a result, even in the case of the “H-L” recording film according tothe present embodiment or in the case where the width Wg of thepre-groove area 11 is wider than the with W1 of the land area, as shownin FIGS. 7B and 7C, a detection signal can be stably obtained from atrack shift detection signal (push-pull signal) or a wobble signal and apre-pit (emboss) area with high precision. The third embodiment is notlimited to AgBi, and a ternary system including AgMg, AgNi, AgGa, AgNx,AgCo, AgAl or the atoms described previously may be used as a silverallow which produces a passive coat film. The thickness of this lightreflection layer 4-2 is set in the range of 5 nm to 200 nm. If thethickness is smaller than 5 nm, the light reflection layer 4-2 is notuniform, and is formed in a land shape. Therefore, the thickness of thelight reflection layer 4-2 is set to 5 nm. When an AgBi film is equal toor smaller than 80 nm in thickness, the film permeates to its back side.Thus, in the case of a one-sided single recording layer, the thicknessis set in the range of 80 nm to 200 nm, and preferably, in the range of100 nm to 150 nm. In the case of a one-sided double recording layer, thethickness is set in the range of 5 nm to 15 nm.

6-2) Description Relating to Pre-Pit Shape in Coating Type Organic DyeRecording Film and On Light Reflection Layer Interface

In an H format according to the present embodiment, the system lead-inarea SYLDI is provided. In this area, an emboss pit area 211 is providedand information is recorded in advance in the form of a pre-bit. Areproduction signal in this area is adjusted to conform to reproductionsignal characteristics from a read-only type information storage medium,and a signal processor circuit in an information reproducing apparatusor an information recording/reproducing apparatus shown in FIG. 8 iscompatible with a read-only type information storage medium and awrite-once type information storage medium. A definition relevant to asignal detected from this area is adjusted to conform to a definition of“3-4): Description of characteristics relating to “H-L” recording filmin the invention”. That is, a reproduction signal amount from the spacearea 14 having a sufficiently large length (11T) is defined as I_(11H),and a reproduction signal from the pre-pit (emboss) area 13 having asufficiently large length (11T) is defined as In addition, adifferential value between these amounts is defined asI₁₁=I_(11H)−I_(11L). In the present embodiment, in accordance with thereproduction signal characteristics from the read-only type informationstorage medium, the reproduction signal in this area is set to be:

I ₁₁ /I _(11H)≧0.3   (54)

and desirably, is set to be:

I ₁₁ /I _(11H)>0.5   (55)

When a repetitive signal amplitude of the space area 14 relevant to thepre-pit (emboss) area 13 having a 2t length is defined as I₂, theamplitude is set to be:

I ₂ /I ₁₁≧0.5   (56)

and desirably, is set to be:

I ₂ /I ₁₁>0.7   (57)

A description will be given with respect to a physical condition formeeting the above formula (54) or formula (55).

As has been described in FIG. 1B, the signal characteristics from apre-pit are mainly dependent on the reflection in the light reflectionlayer 4-2. Therefore, the reproduction signal amplitude value I₁₁ isdetermined depending on a step amount Hpr between the space area 14 andthe pre-pit (emboss) area 13 in the light reflection layer 4-2. Whenoptical approximation calculation is made, this step amount Hpr, withrespect to a reproduction light wavelength λ and a refractive index n₃₂in the recording layer 3-2, has the following relationship:

I₁₁ ∝ sin²{(2π×Hpr×n₃₂)/λ}  (58)

From formula (58), it is found that I₁₁ becomes maximal whenHpr≅π/(4×n₃₂). In order to meet formula (54) or formula (55), fromformula (58), it is necessary to meet:

Hpr≧λ/(12×n ₃₂)   (59)

and desirably,

Hpr>λ/(6×n ₃₂)   (60)

As described in “Chapter 0: Description of Relationship between UseWavelength and the Present Embodiment”, λ=355 nm to 455 nm is used inthe embodiment, and as described in “2-1) Difference in Principle ofRecording/Recording Film and Difference in Basic Concept Relating toGeneration of Reproduction Signal”, n₃₂=1.4 to 1.9 is established. Thus,when this value is substituted into formula (59) or formula (60), a stepis produced so as to meet a condition:

Hpr≧15.6 nm   (62)

and desirably,

Hpr>31.1 nm   (63)

In the conventional write-once type information storage medium, thethickness of the recording layer 3-2 is small in the space area 14, andthus, a step on an interface between the light reflection layer 4-2 andthe recording layer 3-2 is small, and formula (62) has not successfullymet. In contrast, in the present embodiment, a contrivance has been madeto ensure that a relationship between the thickness Dg of the recordinglayer 3-2 in the pre-pit (emboss) area 13 and the thickness Dl of therecording layer 3-2 in the space area 14 conform with a conditiondescribed in “3-2-E] Basic characteristics relating to thicknessdistribution of recording layer in the present embodiment for definitionof parameters”. As a result, a sufficiently large step Hpr which meetsformula (62) or formula (63) has been successfully provided.

By carrying out optical approximation discussion as described above, inthe present embodiment, in order to have sufficient resolution of areproduction signal so as to meet formula (56) or formula (57), acontrivance is made so that the width Wp of the pre-pit (emboss) area 13is equal to or smaller than half of track pitches, and a reproductionsignal from the pre-pit (emboss) area 13 can be largely taken.

Chapter 7: Description of H Format

Now, an H format in the present embodiment will be described here.

FIG. 14 shows a structure and dimensions of an information storagemedium in the present embodiment. As embodiments, there are explicitlyshown three types of embodiments of information storage mediums such as:

“read-only type information storage medium” used exclusively forreproduction in which recording cannot be carried out;

“write-once type information storage medium” capable of additionalrecording; and

“rewritable type information storage medium” capable of rewriting orrecording any times

As shown in FIG. 14, the above three types of information storagemediums are common to each other in a majority of structure anddimensions. In all of the three types of information storage mediums,from their inner periphery side, a burst cutting area BCA, a systemlead-in area SYLDI, a connection area CNA, a data lead-in area DTLSI,and a data area DTA have been arranged. All the mediums other than anOPT type read-only medium is featured in that a data lead-out area DTLDOis arranged at the outer periphery. As described later, in the OPT typeread-only medium, a middle area MDA is arranged at the outer periphery.In either of the write-once type and rewritable type mediums, the insideof this area is for read-only (additional writing disabled). In theread-only type information storage medium, information is recorded inthe data lead-in area DTLDI in the form of emboss (pre-pit). Incontrast, in the write-once type and the rewritable type informationstorage medium, new information can be additionally written (rewrittenin the rewritable type) by forming a recording mark in the data lead-inarea DTLDI. As described later, in the write-once type and rewritabletype information storage medium, in the data lead-out area DTLDO, therecoexist an area in which additional writing can be carried out(rewriting can be carried out in the rewritable type) and a read-onlyarea in which information is recorded in the form of emboss (pre-pit).As described previously, in the data area DTA, data lead-in area DTLVI,data lead-out area DTSDO, and middle area MDA shown in FIG. 14, highdensity of the information storage medium is achieved (in particular,line density is improved) by using a PRML (Partial Response MaximumLikelihood) method for reproduction of signals recorded therein. Inaddition, in the system lead-in area SYLDI and the system lead-out areaSYLDO, compatibility with a current DVD is realized and the stability ofreproduction is improved by using a slice level detecting system forreproduction of signals recorded therein.

Unlike the current DVD specification, in the embodiment shown in FIG.14, the burst cutting area BCA and system lead-in area SYLDI areseparated from each other in location without being superimposed on eachother. These areas are physically separated from each other, therebymaking it possible to prevent interference between the informationrecorded in the system lead-in area SYLDI at the time of informationreproduction and the information recorded in the burst cutting area BCAand to allocate information reproduction with high precision.

Now, a description will be given with respect to internal signalcharacteristics and data structure of a burst cutting area BCA shown inFIG. 14. At the time of measuring a BCA signal, a focusing spot of laserlight beams emitted from an optical head needs to be focused on arecording layer. A reproduction signal obtained in the following burstcutting area BCA is filtered by means of a secondary low-pass vesselfilter for a shutdown frequency of 550 kHz. The following signalcharacteristics of the burst cutting area BCA are defined in the rangeof 22.4 mm to 23.0 mm in radius from the center in the informationstorage medium. With respect to a reproduction signal from the burstcutting area BCA, the maximum and minimum levels when a BCA code and achannel bit are set to “0” are defined as IBHmax and IBHmin; and themaximum bottom level of the BCA code and a channel bit “1” is defined asIBLmax. In addition, an intermediate level is defined as(IBHmin+IBLmax)/2.

In the present embodiment, detection signal characteristics are definedunder a condition that (IBLmax/IBHmin) is 0.8 or less and under acondition that (IBHmax/IBHmin) is 1.4 or less. While an average levelbetween IBL and IBH is defined as a reference, a position at which theBCA signal crosses the reference position is regarded as an edgeposition. The cycle of the BCA signal is defined when a rotation speedis 2760 rpm (46.0 Hz). A cycle between the front-end edges (the fallingpositions) is defined as 4.63×n±1.00 μs, and a width of a pulse positionin location in which an amount of light is lowered (an interval from afirst fall position to a next fall position) is defined as 1.56±0.75 μs.

The BCA code is often recorded after manufacture of an informationstorage medium has been terminated. However, the BCA code may berecorded in advance as a pre-pit. The BCA code is recorded in adirection along the circumference of the information storage medium.This BCA code is also recorded so that a direction in which a pulsewidth narrows coincides with a direction in which a light reflectivityis lowered. The BCA code is recorded after modulated in accordance withan RZ modulating method. A pulse having a narrow pulse width (=having alow reflectivity) needs to be narrower than half of a channel clockwidth of the thus modulated BCA code.

FIG. 28 shows a BCA data structure. BCA data contains two BCA preambles73 and 74, two post-ambles 76 and 77, and two BCA data areas BCAA. A BCAerror detection code EDC_(BCA) and a BCA error correction code ECC_(BCA)are added to each of the BCA data areas BCAA, and a BCA link area 75 isallocated therebetween. Further, a sync byte SB_(BCA) or re-syncRS_(BCA) for each byte is inserted on a four by four byte basis. Theforegoing BCA preambles 73 and 74 each are composed of 4 bytes, and allsettings “00h” are recorded. In addition, the sync byte SB_(BCA) isallocated immediately preceding each of the BCA preambles 73 and 74. 76bytes are set in the BCA data area BCAA. The BCA post-ambles 76 and 77each are composed of 4 bytes, and a repetition pattern of all settings“55h” is recorded. The BCA link area 75 is composed of 4 bytes, and allsettings “AAh” are repeatedly recorded.

FIGS. 29A to 29G each show an example of the contents of the BCAinformation recorded in a BCA data area. The BCA data area BCAA iscapable of recording 76-type information, and data is recorded in unitsof BCA record units BCAU. The information recorded in this BCA recordunit internal BCAU is referred to as a BCA record. The size of each BCArecord is produced as an integer multiple of 4 bytes. In each of the BCArecords, as shown in FIG. 29C, there are sequentially recorded: BCArecord ID 61 composed of 2 bytes; version number information 62 composedof 1 byte; data length information 63 on recording data composed of 1byte; and a data record (recording data 64) of 4 m bytes. The IDs to beset in BCA record ID 61 are assigned in the range of 0000h to 7FFFFh inaccordance with a publicly acceptable utilizing method, and from 8000hto FFFFh are assigned in accordance with an individual utilizing method.The version number information 62 composed of 1 byte is divided intomajor number 71 of the significant 4 bits and minor number 72 of theleast significant 4 bits. The first integer digit of version number isrecorded in major number 71, and a value of a first digit after thedecimal point of version number is recorded in minor number 72. Forexample, in the case of version “2.4”, number “2” is recorded in thefield of major number 71, and number “4” is recorded in the field ofminor number 72.

In the H format according to the present embodiment, identificationinformation 80 on an HD DVD standard type is recorded in the BCA record,as shown in FIG. 29E. Specifically, with respect to the contents of thisinformation, as shown in FIG. 29F, there are recorded: BCA record ID 81;version number information 82; and data length information 83 onrecording data. In addition, there are recorded: standard typeinformation 84 composed of 4 bits; disc type information 85 composed of4 bits; extended part version information 86 (1 byte); and a reservedarea 87 (2 bytes). Recording mark polarity (identification of H-L orL-H) information 88 is allocated in the significant 1 bit in the disctype information 85, and the remaining 3 bits are assigned to a reservedarea 89.

The following configuration can be provided as another example of thedata structure shown in FIGS. 29A to 29G. That is, the BCA recordrecorded in the BCA record unit BCAU #1 (8 bytes) shown in FIG. 29B cancontain the following items of information in the following order:

1) “BCA Record ID” of 2 bytes that is an HD DVD book type identifier;

2) “Version number” of 1 byte indicating a version number;

3) “Data length” of 1 byte indicating a data length;

4) “Book type and Disc type” of 1 byte indicating a book type and a disctype;

5) “Extended Part version” of 1 byte indicating an extended portionversion; and

6) Reserved 2 bytes.

Here, “Disc type” included in the above “Book type and Disc type” isconfigured so that “Mark polarity” and “Twin format flag” can bedescribed. The “Mark polarity” described in this “Disc type” is providedas information that corresponds to the “recording mark polarityinformation 88” described previously. When “Mark polarity=0b”, itindicates “Low-to-High disc” featured in that “a signal from a mark isgreater than a signal from a space”; and when “Mark polarity=1b”, itindicates “High-to-Low disc” featured in that “a signal from a mark issmaller than a signal from a space”.

On the other hand, “Twin format flag” described in “Disc type” isprovided as information indicating whether or not the disc is a twinformat disc. “Twin format flag=0b” indicates that the disc is not a twinformat disc, and “Twin format flag=1b” indicates that the disc is a twinformat disc. The “twin format disc” described herein is a disc featuredin that the disc has two recording/reproducing layers of differentformats (other formats defined in a DVD forum) depending onrecording/reproducing layers are applied. This “Twin format flag” isprovided as a BCA record, whereby, in individual multi-layered HD DVD-R(High Definition DVD Recordable) disc, it is possible to easilydiscriminate whether the disc is a single format disc or a multi-formatdisc.

As shown in FIG. 28, the same information as those contained in a BCAdata area BCAA surrounded by a BCA preamble 73 and a BCA post-amble 76is described in a BCA data area BCAA surrounded by a BCA preamble 74 anda BCA post-amble 77. In this manner, the same information is multiplywritten into the plurality of BCA data areas BCAA. Thus, even if oneitem of data cannot be reproduced due to an effect of dust or scratchproduced on a surface of an information storage medium, data can bereproduced from the other BCA data area BCAA. As a result, thereliability of the data recorded in the BCA data area BCAA is remarkablyimproved.

Further, in the BCA data structure shown in FIG. 28, in addition to theBCA error detection code EDC_(BCA) that exists conventionally, a BCAerror correction code ECC_(BCA) further exists. Thus, even if an erroroccurs with the data contained in the BCA data area BCAA, such an errorcan be corrected by the BCA error correction code ECC_(BCA), and thereliability is further improved.

In the case where an “L-H” type recording film has been used as anotherembodiment, there is a method for forming fine irregularities in advancein location for allocating the burst cutting area BCA.

As described later, the present embodiment also considers a case ofusing the “L-H” recording film. Data recorded in the burst cutting areaBCA (barcode data) is formed by locally carrying out laser exposure to arecording film. The system lead-in area SYLDI is formed of the embossbit area, and thus, the reproduction signal from the system lead-in areaSYLDI appears in a direction in which a light reflection amountdecreases as compared with a light reflection level from the mirrorsurface. If while the burst cutting area BCA is formed as the mirrorsurface, in the case where the “L-H” recording film has been used, areproduction signal from the data recorded in the burst cutting area BCAappears in a direction in which a light reflection amount increases moresignificantly than a light reflection level from the mirror surface (inan unrecorded state). As a result, a significant step occurs between aposition (amplitude level) of a maximum level and a minimum level of thereproduction signal from the data recorded in the burst cutting area BCAand a position (amplitude level) of a maximum level and a minimum levelof the reproduction signal from the system lead-in area SYLDI. Aninformation reproducing apparatus or an informationrecording/reproducing apparatus carry out processing in accordance withthe steps of:

1) reproducing information in the burst cutting area BCA;

2) reproducing information contained in a information data zone CDZ inthe system lead-in area SYLDI;

3) reproducing information contained in the data lead-in area DTLDI (inthe case of write-once type or rewriting type);

4) readjusting (optimizing) a reproduction circuit constant in areference code recording zone RCZ; and

5) reproducing information recorded in the data area DTA or recordingnew information.

Thus, if there exists a large step between a reproduction signalamplitude level from the data formed in the burst cutting area BCA and areproduction signal amplitude level from the system lead-in area SYLDI,there occurs a problem that the reliability of information reproductionis lowered. In order to solve this problem, in the case where the “L-H”recording film is used as a recording film, the present embodiment isfeatured in that fine irregularities are formed in advance in thus burstcutting area BCA. When such fine irregularities are formed, the lightreflection level becomes lower than that from the mirror surface 210 dueto a light interference effect at the stage prior to recording data(barcode data) by local laser exposure. Then, there is attained anadvantageous effect that a step is remarkably decreased between areproduction signal amplitude level (detection level) from the dataformed in the burst cutting area BCA and a reproduction signal amplitudelevel (detection level) from the system lead-in area SYLDI; thereliability of information reproduction is improved; and processinggoing from the above item (1) to item (2) is facilitated.

In the case of using the “L-H” recording film, the specific contents offine irregularities formed in advance in the burst cutting area BCAinclude the emboss pit area 211 like the system lead-in area SYLDI.Another embodiment includes a method for forming the groove area 214 orthe land area and the groove area 213 like the data lead-in area DTLDIor data area DTA. As has been described in the description ofembodiments in which the system lead-in area SYSDI and burst cuttingarea BCA are separately arranged, if the burst cutting area BCA and theemboss bit area 211 overlaps each other, there increases a noisecomponent from the data provided in the burst cutting area BCA due tounnecessary interference to a reproduction signal.

When the groove area 214 or the land area and groove area 213 is formedwithout forming the emboss pit area 211 as an embodiment of the fineirregularities in the burst cutting area BCA, there is attained anadvantageous effect that there decreases a noise component from the dataformed in the burst cutting area BCA due to unnecessary interference toa reproduction signal and the quality of a reproduction signal isimproved.

When track pitches of the groove area 214 or the land area and groovearea 213 formed in the burst cutting area BCA are adjusted to conformwith the those of the system lead-in area SYLDI, there is attained anadvantageous effect that the manufacturing performance of theinformation storage medium is improved. That is, at the time of originalmaster manufacturing of the information storage medium, emboss pits inthe system lead-in area are produced while a feed motor speed is madeconstant. At this time, the track pitches of the groove area 214 or theland area and groove area 213 formed in the burst cutting area BCA areadjusted to conform with those of the emboss pits in the system lead-inarea SYLDI, thereby making it possible to continuously maintain aconstant motor speed in the burst cutting area BCA and the systemlead-in area SYLDI. Thus, there is no need for changing the speed of thefeed motor midway, and thus, the pitch non-uniformity hardly occurs, andthe manufacturing performance of the information storage medium isimproved.

The rewritable type information storage medium has higher recordingcapacity than the read-only type or write-once type information storagemedium by narrowing track pitches and line density (data bit length). Asdescribed later, in the rewritable type information storage medium, thetrack pitches are narrowed by reducing effect of a cross-talk of theadjacent tracks by employing land-groove recording. Alternatively, anyof the read-only type information storage medium, write-once informationstorage medium, and rewritable-type information storage medium isfeatured in that the data bit length and track pitches (corresponding torecording density) of the system lead-in/system lead-out areasSYLDI/SYLDO are greater than those of the data lead-in/data lead-outarea DTLDI/DTLDO (in that the recording density is low).

The data bit length and track pitches of the system lead-in/systemlead-out areas SYLDI/SYLDO are close to the values of the current DVDlead-in area, thereby realizing compatibility with the current DVD.

In the present embodiment as well, like the current DVD-R, an embossstep in the system lead-in/system lead-out areas SYLDI/SYLDO of thewrite-once type information storage medium is shallowly defined. In thismanner, there is attained advantageous effect that a depth of apre-groove of the write-once information storage medium is shallowlydefined and a degree of modulation of a reproduction signal from arecording mark formed on a pre-groove by additional writing isincreased. In contrast, as a counteraction against it, there occurs aproblem that the degree of modulation of the reproduction signal fromthe system lead-in/system lead-out areas SYLDI/SYLDO decreases. In orderto solve this problem, the data bit length (and track pitches) of systemlead-in/system lead-out areas SYLDI/SYLDO are roughened and a repetitionfrequency of pits and spaces at the narrowest position is isolated(significantly reduced) from an optical shutdown frequency of an MTF(Modulation Transfer Function) of a reproduction objective lens, therebymaking it possible to increase the reproduction signal amplitude fromthe system lead-in/system lead-out areas SYLDI/SYLDO and to stabilizereproduction.

The initial zone INZ indicates a start position of the system lead-inarea SYLDI, as shown in FIGS. 15A to 15D. As significant informationrecorded in the initial zone INZ, there is discretely arranged data ID(Identification Data) information including information on physicalsector numbers or logical sector numbers described previously. Asdescribed later, one physical sector records information on a data framestructure composed of data ID, IED (ID Error Detection code), main datafor recording user information, and EDC (Error detection code); and theinitial zone records information on the above described data framestructure. However, in the initial zone INZ, all the information on themain data for recording the user information is all set to “00h”, andthus, the significant information contained in the initial zone INZ isonly data ID information. A current location can be recognized from theinformation on physical sector numbers or logical sector numbersrecorded therein. That is, when an information recording/reproducingunit 141 shown in FIG. 8 starts information reproduction from aninformation storage medium, in the case where reproduction has beenstarted from the information contained in the initial zone INZ, first,the information on physical sector numbers or logical sector numbersrecorded in the data ID information is sampled, and the sampledinformation is moved to the control data zone CDZ while the currentlocation in the information storage medium is checked.

A buffer zone 1 BFZ1 and a buffer zone 2 BFZ2 each are composed of 32ECC blocks. One ECC block corresponds to 1024 physical sectors. In thebuffer zone 1 BFZ1 and the buffer zone 2 BFZ2 as well, like the initialzone INZ, main data information is set to all “00h”.

The connection zone CNZ which exists in a CNA (Connection Area) is anarea for physically separating the system lead-in area SYLDI and thedata lead-in area DTLDI from each other. This area is provided as amirror surface on which no emboss pit or pre-groove exists.

An RCZ (Reference code zone) of the read-only type information storagemedium and the write-once type information storage medium each is anarea used for reproduction circuit tuning of a reproducing apparatus,wherein information on the data frame structure described previously isrecorded. A length of the reference code is one ECC block (=32 sectors).The present embodiment is featured in that the RCZ (Reference code zone)of the read-only type information storage medium and the write-onceinformation storage medium each is arranged adjacent to a DTA (dataarea). In any of the structures of the current DVD-ROM disc and thecurrent DVD-R disc as well, a control data zone is arranged between thereference code zone and data area, and the reference code zone and thedata area are separated from each other. If the reference code zone anddata area are separated from each other, a tilt amount or a lightreflection factor of the information storage medium or the recordingsensitivity of a recording film (in the case of the write-onceinformation storage medium) slightly changes. Therefore, there occurs aproblem that an optimal circuit constant in the data area is distortedeven if a circuit constant of the reproducing apparatus is adjusted. Inorder to solve the above described problem, when the RCZ (reference codezone) is arranged adjacent to the DTA (data area), in the case where thecircuit constant of the information reproducing apparatus has beenoptimized in the RCZ (reference code zone), an optimized state ismaintained by the same circuit constant in the DTA (data area). In thecase where an attempt is made to precisely reproduce a signal inarbitrary location in the DTA (data area), it becomes possible toreproduce a signal at a target position very precisely in accordancewith the steps of:

1) optimizing a circuit constant of the information reproducingapparatus in the RCZ (reference code zone);

2) optimizing a circuit constant of the information reproducingapparatus again while reproducing a portion which is the closest to thereference code zone RCZ in the data area DTA;

3) optimizing a circuit constant once again while reproducinginformation at an intermediate position between a target position in thedata area DTA and the position optimized in step (2); and

4) reproducing signal after moving to the target position.

GTZ1 and GTZ2 (guard track zones 1 and 2) existing in the write-onceinformation storage medium and the rewritable-type information storagemedium are areas for specifying the start boundary position of the datalead-in area DTLDI, and a boundary position of a drive test zone DRTZand a disc test zone DKTZ. These areas are prohibited from beingrecorded a recording mark. The guard track zone 1 GTZ1 and guard trackzone 2 GTZ2 exist in the data lead-in area DTLDI, and thus, in thisarea, the write-once type information storage medium is featured in thatthe pre-groove area is formed in advance. Alternatively, therewritable-type information storage medium is featured in that thegroove area and the land area are formed in advance. In the pre-groovearea or groove area and the land area, wobble addresses are recorded inadvance, and thus, the current location in the information storagemedium is determined by using these wobble addresses.

The disc test zone DKTZ is an area provided for manufactures ofinformation storage mediums to carry out quality test (evaluation).

The drive test zone DRTZ is provided as an area for carrying out testwriting before the information recording/reproducing apparatus recordsinformation in the information storage medium. The informationrecording/reproducing apparatus carries out test writing in advance inthis area, and identifies an optimal recording condition (writestrategy). Then, the information contained in the data area DTA can berecorded under the optimal recording condition.

The information recorded in the disc identification zone DIZ whichexists in the rewritable-type information storage medium is an optionalinformation recording area, the area being adopted to additionally writea set of drive descriptions composed of: information on manufacturername of recording/reproducing apparatuses; additional informationrelating thereto; and an area in which recording can be uniquely carriedout by the manufacturers.

A defect management area 1 DMA1 and a defect management area 2 DMA2which exist in a rewritable-type information storage medium recorddefect management information contained in the data area DTA, and, forexample, substitute site information when a defect occurs or the like isrecorded.

In the write-once type information storage medium, there exist uniquely:an RMD duplication zone RDZ; a recording management zone RMZ; and an Rphysical information zone R-PFIZ. The recording management zone RMZrecords RMD (recording management data) which is an item of managementinformation relating to a recording position of data updated byadditional writing of data. A detailed description will be given later.As described later in FIGS. 15A, 15B, 15C, and 15D, in the presentembodiment, a recording management zone RMZ is set for each borderedarea BRDA, enabling area expansion of the recording management zone RMZ.As a result, even if the required recording management data RMDincreases due to an increase of additional writing frequency, such anincrease can be handled by extending the recording management zone RMZin series, and thus, there is attained advantageous effect that theadditional writing count can be significantly increased. In this case,in the present embodiment, the recording management zone RMZ is arrangedin a border-in BRDI which corresponds to each bordered area BRDA(arranged immediately before each bordered area BRDA). In the presentembodiment, the border-in BRDI corresponding to the first bordered areaBRDA #1 and a data lead-in area DTLDI are made compatible with eachother, and efficient use of the data area DTA is promoted while theforming of the first border-in BRDI in the data area DTA is eliminated.That is, the recording management zone RMZ in the data lead-in area DTAis utilized as a recording location of the recording management data RDMwhich corresponds to the first bordered area BRDA #1.

The RMD duplication zone RDZ is a location for recording information onthe recording management data RMD which meets the following condition inthe recording management zone RMZ, and the reliability of the recordingmanagement data RMD is improved by providing the recording managementdata RMD in a duplicate manner, as in the present embodiment. That is,in the case where the recording management data RMD contained in therecording management zone RMZ is valid due to dust or scratch adheringto a write-once information storage medium surface, the recordingmanagement data RMD is reproduced, the data being recorded in this RMDduplication zone RDZ. Further, the remaining required information isacquired by tracing, whereby information on the latest recordingmanagement data RMD can be restored.

This RMD duplication zone records recording management data RDM at atime point at which (a plurality of) borders are closed. As describedlater, a new recording management zone RMZ is defined every time oneborder is closed and a next new bordered area is set. Thus, every time anew recording management zone RMZ is created, the last recordingmanagement data RMD relating to the preceding bordered area may berecorded in this RMD duplication zone RDZ. When the same information isrecorded in this RMD duplication zone RDZ every time the recordingmanagement data RDM is additionally recorded on a write-once informationstorage medium, the RMD duplication zone RDZ becomes full with acomparatively small additional recording count, and thus, an upper limitvalue of the additional writing count becomes small. In contrast, as inthe present embodiment, in the case where a recording management zone isnewly produced when a border is closed, the recording management zone inthe border-in BRDI becomes full, and a new recording management zone RMZis formed by using an R zone, there is attained advantageous effect thatonly the last recording management data RMD contained in the pastrecording management zone RMZ is recorded in the RMD duplication zoneRDZ, thereby making it possible to improve an allowable additionalwriting count by efficiently using the RMD duplication zone RDZ.

For example, in the case where the recording management data RMDcontained in the recording management zone RMZ which corresponds to thebordered area BRDA on the way of additional writing (before closed)cannot be reproduced due to the dust or scratch adhering to the surfaceof the write-once type information storage medium, a location of thebordered area BRDA, which has been already closed, can be identified byreading the recording management data RMD lastly recorded in this RMDduplication zone RDZ. Therefore, the location of the bordered area BRDAon the way of additional writing (before closed) and the contents ofinformation recorded therein can be acquired by tracing another locationin the data area DTA of the information storage medium, and theinformation on the latest recording management data RMD can be restored.

An R physical information zone R-PFIZ records the information analogousto the physical format PFI contained in the control data zone CDZ(described later in detail).

FIG. 15C shows a data structure in the RMD duplication zone RDZ and therecording management zone RMZ which exists in the write-once typeinformation storage medium. FIG. 15B shows an enlarged view of the RMDduplication zone RDZ and the recording management zone RDZ. As describedabove, in the recording management zone RMZ contained in the datalead-in area DTLDI, data relating to recording management whichcorresponds to the first bordered area BRDA is collectively recorded,respectively, in one items of recording management data (RMD); and newrecording management data RMD is sequentially additionally written atthe back side every time the contents of the recording management dataRMD generated when additional writing process has been carried out inthe write-once information storage medium are updated. That is, the RMD(Recording Management Data) is recorded in size units of single physicalsegment block (a physical segment block will be described later), andnew recording management data RMD is sequentially additionally writtenevery time the contents of data are updated. In the example shown inFIG. 15B, a change has occurred with management data in locationrecording management data RMD #1 and RMD #2 has been recorded. Thus,this figure shows an example in which the data after changed (afterupdated) has been recorded as recording management data RMD #3immediately after the recording management data RMD #2. Therefore, inthe recording management zone RMD, a reserved area 273 exists so thatadditional writing can be further carried out.

Although FIG. 15B shows a structure in the recording management zone RMZwhich exists in the data lead-in area DTLDI, a structure in therecording management zone RMZ (or extended recording management zone:referred to as extended RMZ) which exists in the border-in BRDI orbordered area BRDA described later is also identical to the structureshown in FIG. 15B without being limited thereto.

In the present embodiment, in the case where a first bordered area BRDA#1 is closed or in the case where the terminating process (finalizing)of the data area DTA is carried out, a processing operation for paddingall the reserved area 273 shown in FIG. 15B with the latest recordingmanagement data RMD duplication zone is carried out. In this manner, thefollowing advantageous effects are attained:

1) An “unrecorded” reserved area 273 is eliminated, and thestabilization of tracking correction due to a DPD (Differential PhaseDetection) technique is guaranteed;

2) the latest recording management data RMD is overwritten in the pastreserved area 273, thereby remarkably improving the reliability at thetime of reproduction relating to the last recording management data RMD;and

3) an event that different items of recording management data RMD aremistakenly recorded in an unrecorded reserved area 273 can be prevented.

The above processing method is not limited to the recording managementzone RMZ contained in the data lead-in area DTLDI. In the presentembodiment, with respect to the recording management zone RMZ (orextended recording management zone: referred to as extended RMZ) whichexists in the border-in BRDI or bordered area BRDA described later, inthe case where the corresponding bordered area BRDA is closed or in thecase where the terminating process (finalizing) of the data area DTA iscarried out, a processing operation for padding all the reserved area273 shown in FIG. 15B with the latest recording management data RMD iscarried out.

The RMD duplication zone RDZ is divided into the RDZ lead-in area RDZLIand a recording area 271 of the last recording management data RMDduplication zone RDZ of the corresponding RMZ. The RDZ lead-in areaRDZLI is composed of a system reserved field SRSF whose data size is 48KB and a unique ID field UIDF whose data size is 16 KB, as shown in FIG.15B. All “00h” are set in the system reserved field SRSF.

The present embodiment is featured in that DRZ lead-in area RDZLI isrecorded in the data lead-in area DTLDI which can be additionallywritten. In the write-once type information storage medium according tothe present embodiment, the medium is shipped with the RDZ lead-in areaRDZLI being in an unrecorded state immediately after manufacturing. Inthe user's information recording/reproducing apparatus, at a stage ofusing this write-once type information storage medium, RDZ lead-in areaRDZLI information is recorded. Therefore, it is determined whether ornot information is recorded in this RDZ lead-in area RDZLI immediatelyafter the write-once type information storage medium has been mounted onthe information recording/reproducing apparatus, thereby making itpossible to easily know whether or not the target write-once typeinformation storage medium is in a state immediately aftermanufacturing/shipment or has been used at least once. Further, as shownin FIGS. 15A to 15D, the present embodiment is secondarily featured inthat the RMD duplication zone RDZ is provided at the inner peripheryside than the recording management zone RMZ which corresponds to a firstbordered area BRDA, and the RDZ lead-in RDZLI is arranged in the RMDduplication zone RDZ.

The use efficiency of information acquisition is improved by arranginginformation (RDZ lead-in area RDZLI) representing whether or not thewrite-once type information storage medium is in a state immediatelyafter manufacturing/shipment or has been used at least once in the RMDduplication zone RDZ used for the purpose of a common use (improvementof reliability of RMD). In addition, the RDZ lead-in area RDZLI isarranged at the inner periphery side than the recording management zoneRMZ, thereby making it possible to reduce a time required foracquisition of required information. When the information storage mediumis mounted on the information recording/reproducing apparatus, theinformation recording/reproducing apparatus starts reproduction from theburst cutting area BCA arranged at the innermost periphery side, asdescribed in FIG. 14, and sequentially changes a reproducing locationfrom the system lead-in SYLSI to the data lead-in area DTLDI while thereproduction position is sequentially moved to the innermost peripheryside. It is determined whether or not information has been recorded inthe RDZ lead-in area RDZLI contained in the RMD duplication zone RDZ. Ina write-once type information storage medium in which no recording iscarried out immediately after shipment, no recording management data RMDis recorded in the recording management zone RMZ. Thus, in the casewhere no information is recorded in the RDZ lead-in area RDZLI, it isdetermined that the medium is “unused immediately after shipment”, andthe reproduction of the recording management zone RMD can be eliminated,and a time required for acquisition of required information can bereduced.

As shown in FIG. 15C, a unique ID area UIDF records information relatingto an information recording/reproducing apparatus for which thewrite-once type information storage medium immediately after shipmenthas been first used (i.e., for which recording has been first started).That is, this area records a drive manufacturer ID 281 of theinformation recording/reproducing apparatus or serial number 283 andmodel number 284 of the information recording/reproducing apparatus. Theunique ID area UIDF repeatedly records the same information for 2 KB(strictly, 2048 bytes) shown in FIG. 15C. Information contained in theunique disc ID 287 records year information 293, month information 294,date information 295, time information 296, minutes information 297, andseconds information 298 when the storage medium has been first used(recording has been first started). A data type of respective items ofinformation is described in HEX, BIN, ASCII as described in FIG. 15D,and two types or four bytes are used.

The present embodiment is featured in that the size of an area of thisRDZ lead-in area RDZLI and the size of the one recording management dataRMD are 64 KB, i.e., the user data size in one ECC block becomes aninteger multiple. In the case of the write-once type information storagemedium, it is impossible to carry out a processing operation forrewriting ECC block data after changed in the information storage mediumafter changing part of the data contained in one ECC block. Therefore,in particular, in the case of the write-once type information storagemedium, as described later, data is recorded in recording cluster unitscomposed of an integer multiple of a data segment including one ECCblock. Therefore, the size of the area of the RDZ lead-in area RDZLI andthe size of such one item of recording management data RMD are differentfrom a user data size in an ECC block, there is a need for a paddingarea or a stuffing area for making adjustment to the recording clusterunit, and a substantial recording efficiency is lowered. As in thepresent embodiment, the size of the area of the RDZ lead-in area RDZLIand the size of such one item of recording management data RMD are setto an integer multiple of 64 KB, thereby making it possible to lower therecording efficiency.

A description will be given with respect to a last recording managementdata RMD recording area 271 of the corresponding RMZ shown in FIG. 15B.As described in Japanese Patent No. 2621459, there is a method forrecording intermediate information at the time of interruption ofrecording inwardly of the lead-in area. In this case, every timerecording is interrupted or every time an additional writing process iscarried out, it is necessary to serially additionally write intermediateinformation in this area (recording management data RMD in the presentembodiment). Thus, if such recording interruption or additional writingprocess is frequently repeated, there is a problem that this areabecomes full immediately and a further adding process cannot be carriedout. In order to solve this problem, the present embodiment is featuredin that an RMD duplication zone RDZ is set as an area capable ofrecording the recording management data RMD updated only when a specificcondition is met and the recording management data RMD sampled undersuch a specific condition is recorded. Thus, there is attainedadvantageous effect that the RMD duplication zone RDZ can be preventedfrom being full and the numbers of additional writings enable withrespect to the write-once type information storage medium can beremarkably improved by lowering the frequency of the recordingmanagement data RMD additionally written in the RMD duplication zoneRDZ. In parallel to this effect, the recording management data updatedevery time an additional writing process is carried out is seriallyadditionally written in the recording management zone RMZ in theborder-in area BRDI shown in FIG. 15A (in the data lead-in area DTLDI asshown in FIG. 15A with respect to the first bordered area BRDA #1) orthe recording management zone RMZ utilizing an R zone described later.When a new recording management zone RMZ is created, for example, whenthe next bordered area BRDA is created (new border-in area BRDI is set)or when a new recording management zone RMZ is set in an R zone, thelast recording management data RMD (the newest RMD in a stateimmediately before creating a new recording management zone RMZ) isrecorded in (the corresponding last recording management data RMDrecording area 271) contained in the RMD duplication zone RDZ. In thismanner, there is attained advantageous effect that a newest RMD positionsearch is facilitated by utilizing this area in addition to asignificantly increase of additional writing enable count for thewrite-once type information storage medium.

In any of the read-only type, write-once type, and rewritable-typeinformation storage medium, the present embodiment is featured in that asystem lead-in area is arranged at an opposite side of a data area whilea data lead-in area is sandwiched between the two areas, and further, asshown in FIG. 14, the burst cutting area BCA and the data lead-in areaDTLDI are arranged at an opposite side to each other while the systemlead-in area SYSDI is sandwiched between the two areas. When aninformation storage medium is inserted into the information reproducingapparatus or information recording/reproducing apparatus shown in FIG.8, the information reproducing apparatus or informationrecording/reproducing apparatus carries out processing in accordancewith the steps of:

1) reproducing information contained in the burst cutting area BCA;

2) reproducing information contained in the information data zone CDZcontained in the system lead-in area SYLDI;

3) reproducing information contained in the data lead-in area DTLDI (inthe case of a write-once type or a rewritable-type medium);

4) readjusting (optimizing) a reproduction circuit constant in thereference code zone RCZ; and

5) reproducing information recorded in the data area DTA or recordingnew information.

Information is sequentially arranged from the inner periphery side alongthe above processing steps, and thus, a process for providing an accessto an unnecessary inner periphery is eliminated, the number of accessesis reduced, and the data area DTA can be accessed. Thus, there isattained advantageous effect that a start time for reproducing theinformation recording in the data area or recording new information isaccelerated. In addition, RPML is used for signal reproduction in thedata lead-in area DTDLI and data area DTA by utilizing a slice leveldetecting system for signal reproduction in the system lead-in areaSYLDI. Thus, if the data lead-in area DTLDI and the data area DTA aremade adjacent to each other, in the case where reproduction is carriedout sequentially from the inner periphery side, a signal can be stablyreproduced continuously merely by switching a slice level detectingcircuit to a PRML detector circuit only once between the system lead-inarea SYLDI and the data lead-in area DTLDI. Thus, the number ofreproduction circuit switchings along the reproduction procedures issmall, thus simplifying processing control and accelerating a dataintra-area reproduction start time.

In the read-only type information storage medium, the data recorded inthe data lead-out area DTLDO and the system lead-out area SYLDO eachhave a data frame structure (described later in detail) in the samemanner as in the buffer zone 1 BFZ1 and buffer zone 2 BFZ2, and allvalues of the main data contained therein are set to “00h”. In theread-only type information storage medium, a user data prerecording area201 can be fully used in the data area DTA. However, as described later,in any of the embodiments of the write-once information storage mediumand rewritable-type information storage medium as well, userrewriting/additional writing enable ranges 202 to 205 are narrower thanthe data area DTA.

In the write-once information storage medium or rewritable-typeinformation storage medium, an SPA (Spare Area) is provided at theinnermost periphery of the data area DTA. In the case where a defect hasoccurred in the data area DTA, a substituting process is carried out byusing the spare area SPA. In the case of the rewritable-type informationstorage medium, the substitution history information (defect managementinformation) is recorded in a defect management area 1 (DMA1) and adefect management area 2 (DMA2); and a detect management area 3 (DMA3)and a defect management area 4 (DMA4). The defect management informationrecorded in the defect management area 3 (DMA3) and defect managementarea 4 (DMA4) are recorded as the same contents of the defect managementinformation recorded in the defect management information 1 (DMA1) anddefect management information 2 (DMA2). In the case of the write-oncetype information storage medium, substitution history information(defect management information) in the case where the substitutingprocess has been carried out is recorded in the data lead-in area DTLDIand copy information CRMZ on the contents of recoding in a recordingmanagement zone which exists in a border zone. Although defectmanagement has not been carried out in a current DVD-R disc, DVD-R discspartially having a defect location are commercially available as themanufacture number of DVD-R discs increases, and there is a growing needfor improving the reliability of information recorded in a write-oncetype information storage medium.

A drive test zone DRTZ is arranged as an area for test writing before aninformation recording/reproducing apparatus records information in aninformation storage medium. The information recording/reproducingapparatus carries out test writing in advance in this area, andidentifies an optimal recording condition (write strategy). Then, thisapparatus can record information in the data area DTA under the optimalrecording condition.

The disc test zone DKTZ is an area provided for manufacturers ofinformation storage mediums to carry out quality test (evaluation).

In the write-once type information storage medium, two drive test zonesDRTZ are provided at the inner periphery side and the outer peripheryside of the medium. As more test writing operations are carried out forthe drive text zones DRTZ, parameters are finely assigned, therebymaking it possible to search an optimal recording condition in detailand to improve the precision of recording in the data area DTA. Therewritable-type information storage medium enables reuse in the drivetest zone DRTZ due to overwriting. However, if an attempt is made toenhance the recording precision by increasing the number of testwritings in the write-once type information storage medium, there occursa problem that the drive test zone is used up immediately. In order tosolve this problem, the present embodiment is featured in that an EDRTZ(Expanded Drive Test Zone) can be set from the outer periphery to theinner periphery direction, making it possible to extend a drive testzone.

In the present embodiment, features relating to a method for setting anextended drive test zone and a method for carrying out test writing inthe set extended drive test zone are described below.

1) The setting (framing) of extended drive test zones EDRTZ aresequentially provided collectively from the outer periphery direction(close to the data lead-out area DTLDO) to the inner periphery side.

The extended drive test zone 1 (EDRTZ1) is set as an area collected froma location which is the closest to the outer periphery in the data area(which is the closest to the data lead-out area DTLDO); and the extendeddrive test zone 1 (EDRTZ1) is used up, thereby making it possible tosecondarily set the extended drive test zone 2 (EDRTZ2) as a correctedarea which exists in the inner periphery side than the current position.

2) Test writing is sequentially carried out from the inner peripheryside in the extended dive test zone DDRTZ.

In the case where test writing is carried out in the extended drive testzone EDRTZ, such test writing is carried out along a groove area 214arranged in a spiral shape from the inner periphery side to the outerperiphery side, and current test writing is carried out for anunrecorded location that immediately follows the previously test-written(recorded) location.

The data area is structured to be additionally written along the groovearea 214 arranged in a spiral manner from the inner periphery side tothe outer periphery side. A processing operation from “checkingimmediately test-written location” to “carrying out current testwriting” can be serially carried out by using a method for sequentiallycarrying out additional writing a location that follows a test writinglocation in which test writing in the extended drive test zone has beencarried out immediately before, thus facilitating a test writing processand simplifying management of the test-written location in the extendeddrive test zone EDRTZ.

3) The data lead-out area DTLDO can be reset in the form including theextended drive test zone.

two areas, i.e., an extended spare area 1 (ESPA1) and an extended sparearea 2 (ESPA2) are set in the data area DTA and two areas, i.e., theextended drive test zone 1 (EDRTZ1) and extended drive test zone 2(EDRTZ2) are set. The present embodiment is featured in that the datalead-out area DTLO can be reset with respect to an area including up tothe extended drive test zone 2 (EDRTZ2). Concurrently, the range of dataarea DTA is reset in a range-narrowed manner, making it easy to managean additional writing enable range 205 of the user data which exists inthe data area DTA.

In the case where the resetting has been provided, a setting location ofthe extended spare area 1 (ESPA1) is regarded as an “extended spare areawhich has already been used up”, and an unrecorded area (area enablingadditional test writing) is managed only in the extended spare area 2(ESPA2) contained in the extended drive test zone EDRTZ if any. In thiscase, non-defect information which is recorded in the extended sparearea 1 (ESPA1) and which has been used up for substitution istransferred to a location of an area which is not substituted in theextended spare area 2 (ESPTA2), and defect management information isrewritten. The start position information on the reset data lead-outarea DTLDO is recorded in allocation position information on the latest(updated) data area DTA of RMD field 0 contained in the recordingmanagement data RMD. A structure of a border area in a write-once typeinformation storage medium will be described here with reference toFIGS. 17A to 17D. When one border area has been first set in thewrite-once information storage medium, a bordered area (Bordered Area)BRDA #1 is set at the inner periphery size (which is the closest to thedata lead-in area DTLDI), as shown in FIG. 17A, and then, a border out(Border out) BRDO that follows the above area is formed.

Further, in the case where an attempt is made to set a next borderedarea (Bordered Area) BRDA #2, as shown in FIG. 17B, a next (#1) borderin area BRDI that follows the preceding #1 border out area BRDO isformed, and then, a next bordered area BRDA #2 is set. In the case wherean attempt is made to close the next bordered area BRDA #2, a (#2)border out area BRDO that immediately follows the area BRDA #2 isformed. In the present embodiment, a state in which the next ((#1)border in area BRDI) that follows the preceding (#1) border out areaBRDO is formed and combined is referred to as a border zone BRDZ. Theborder zone BRDZ is set to prevent an optical head from overrun betweenthe bordered areas BRDAs when reproduction has been carried out by usingthe information reproducing apparatus (on the presumption that the DPDdetecting technique is used). Therefore, in the case where a write-oncetype information storage medium having information recorded therein isreproduced by using a read-only apparatus, it is presumed that a borderclose process is made such that the border out area BRDO and border-inarea BRDI are already recorded and the border out area BRDO that followsthe last bordered area BRDA is recorded. The first bordered area BRDA #1is composed of 4080 or more physical segment blocks, and there is a needfor the first bordered area BRDA #1 to have a width of 1.0 mm or more ina radial direction on the write-once type information storage medium.FIG. 17B shows an example of setting an extended drive test zone EDRTZin the data area DTA.

FIG. 17C shows a state obtained after finalizing a write-onceinformation storage medium. FIG. 17C shows an example in which anextended drive test zone EDRTZ is incorporated in the data lead-out areaDTLDO, and further, an extended spare area ESPA has been set. In thiscase, a user data adding enable range 205 is fully padded with the lastborder out area BRDO.

FIG. 17D shows a detailed data structure in the border zone area BRDZdescribed above. Each item of information is recorded in size units ofone physical segment blocks (physical segment block). Copy informationC_RMZ on the contents recorded in a recording management zone isrecorded at the beginning of the border out area BRDO, and a border endmark (Stop Block) STB indicating the border out area BRDOP is recorded.Further, in the case the next border in area BDI is reached, a firstmark (Next Border Marker) NBM indicating that a next border area reachesan “N1-th” physical segment block counted from a physical segment blockin which the border end mark (Stop Block) STC has been recorded; asecond mark NBM indicating that a next border region reaches an “N2-th”physical segment block; and a third mark NBM indicating that a nextborder region reaches an “N3-th” mark NBM are discretely recorded in atotal of three locations on a size by size basis of one physical segmentblock, respectively. Updated physical format information UPFI isrecorded in the next border-in area BRDI. In a current DVD-R or a DVD-RWdisc, in the case where a next border is not reached (in the last borderout area BRDO), a location in which “a mark NBM indicating a nextborder” should be recorded (a location of one physical segment blocksize) shown in FIG. 17D is maintained as a “location in which no data isrecorded”. If border closing is carried out in this state, thiswrite-once type information storage medium (current DVD-R or DVD-RWdisc) enters a state in which reproduction can be carried out by using aconventional DVD-ROM drive or a conventional DVD player. Theconventional DVD-ROM drive or the conventional DVD player utilizes arecording mark recorded on this write-once type information storagemedium (current DVD-R or DVD-RW disc) to carry out track shift detectionusing the DPD (Differential Phase Detect) technique. However, in theabove described “location in which no data is recorded”, a recordingmark does not exist over one physical segment block size, thus making itimpossible to carry out track shift detection using the DPD(Differential Phase Detect) technique. Thus, there is a problem that atrack servo cannot be stably applied.

In order to solve the above described problem with the current DVD-R orDVD-RW disc, the present embodiment newly employed methods for:

1) in the case where a next border area is reached, recording data on aspecific pattern in advance in a “location in which the mark NBMindicating a next border should be recorded”; and

2) carrying out an “overwriting process” in a specific recording patternpartially and discretely with respect to a location indicating “the markNBM indicating a next border” in which, in the case where a next borderarea is reached, the data on the specific pattern is recorded inadvance, thereby utilizing identification information indicating that “anext border area is reached”.

By setting a mark indicating a next border due to overwriting, there isattained advantageous effect that, even in the case where a next borderarea is reached as shown in item (1), a recording mark of a specificpattern can be formed in advance in a “location in which the mark NBMindicating a next border should be recorded”, and, after border closing,even if a read-only type information reproducing apparatus carries outtrack shift detection in accordance with the DPD technique, a trackservo can be stably applied. If a new recording mark is overwrittenpartially on a portion at which a recording mark has already been formedin a write-once type information storage medium, there is a danger thatthe stability of a PLL circuit shown in FIG. 8 is degraded in aninformation recording/reproducing apparatus or an informationreproducing apparatus. In order to overcome this danger, the presentembodiment further newly employs methods for:

3) when overwriting is carried out at a position of “the mark NBMindicating a next border” of one physical segment block size, changingan overwrite state depending on a location contained in the same datasegment;

4) partially carrying out overwriting in a sync data 432 and disablingoverwriting on a sync code 431; and

5) carrying out overwriting in a location excluding data ID and IED.

As described later in detail, data fields 411 to 418 for recording userdata and guard areas 441 to 448 are alternately recorded on aninformation storage medium. A group obtained by combining the datafields 411 to 418 and the guard areas 441 to 448 is called a datasegment 490, and one data segment length coincides with one physicalsegment block length. The PLL circuit 174 shown in FIG. 8 facilitatesPLL lead-in in VFO areas 471 and 472 in particular. Therefore, even ifPLL goes out immediately before the VFO areas 471 and 472, PLLre-lead-in is easily carried out by using the VFO areas 471 and 472,thus reducing an effect on a whole system in the informationrecording/reproducing apparatus or information reproducing apparatus.There is attained advantageous effect that (3) an overwrite state ischanged depending on a location in a data segment internal location, asdescribed above, by utilizing this state, and an overwrite amount of aspecific pattern is increased at a back portion close to the VFO areas471 and 472 contained in the same data segment, thereby making itpossible to facilitate judgment of “a mark indicating a next border” andto prevent degradation of the precision of a signal PLL at the time ofreproduction.

One physical sector is composed of a combination of a location in whichsync codes (SY0 to SY3) are arranged and the sync data 434 arrangedbetween these sync codes 433. The information recording/reproducingapparatus or the information recording apparatus samples sync codes 43(SY0 to SY3) from a channel bit pattern recorded on the informationstorage medium, and detects a boundary of the channel bit pattern. Asdescribed later, position information (physical sector numbers orlogical sector numbers) on the data recorded on the information storagemedium is sampled from data ID information. A data ID error is sensed byusing an IED arranged immediately after the sampled information.Therefore, the present embodiment enables (5) disabling overwriting ondata ID and IED and (4) partially carrying out overwriting in the syncdata 432 excluding the sync code 431, thereby enabling detection of adata ID position and reproduction (content-reading) of the informationrecorded in data ID by using the sync code 431 in the “mark NMBindicating a next border”.

FIGS. 16A to 16D show another embodiment which is different from thatshown in FIGS. 17A to 17D relating to a structure of a border area in awrite-once type information storage medium. FIGS. 16A and 16B show thesame contents of FIGS. 17A and 17B. FIGS. 16A to 16D are different fromFIG. 17C in terms of a state that follows finalization of a write-oncetype information storage medium. For example, as shown in FIG. 16C,after information contained in the bordered area BRDA #3 has beenrecorded, in the case where an attempt is made to achieve finalization,a border out area BRDO is formed immediately after the bordered area BDA#3 as a border closing process. Then, a terminator area TRM is formedafter the border out area DRDO which immediately follows the borderedarea BRDA #3, thereby reducing a time required for finalization.

In the embodiment shown in FIGS. 17A to 17D, there is a need for paddinga region that immediately precedes the extended spare area ESPA withborder out area BRDO. There occurs a problem that a large amount of timeis required to form this border out area BRDO, thereby extending thefinalization time. In contrast, in the embodiment shown in FIG. 16C, acomparatively short terminator area TRM is set in length; all of theouter areas than the terminator TRM are redefined as a data lead-outarea NDTLDO; and an unrecorded portion which is outer than theterminator TRM is set as a user disable area 911. That is, when the dataarea DTA is finalized, the terminator area TRM is formed at the end ofrecording data (immediately after the border out area BRDO). All theinformation on the main data contained in this area is set to “00h”.Type information on this area is set in an attribute of the datalead-out area NDTLDO, whereby this terminator area TRM is redefined as anew data lead-out area NDTLDO, as shown in FIG. 16C. Type information onthis area is recorded in area type information 935 contained in data ID,as described later. That is, the area type information 935 contained inthe data ID in this terminator area TRM is set to “10b”, therebyindicating that data exists in the data lead-out area DTLDO. The presentembodiment is featured in that identification information on a datalead-out position is set by the data ID internal area type information935.

In an information recording/reproducing apparatus or an informationreproducing apparatus shown in FIG. 8, let us consider a case in whichan information recording/reproducing unit 141 has provided a randomaccess to a specific target position on a write-once type informationstorage medium. Immediately after random access, the informationrecording/reproducing unit 141 must reproduce a data ID and decode adata frame number 922 in order to know where on the write-once typeinformation storage medium has been reached. In the data ID, area typeinformation 935 exists near the data frame number 922. At the same time,it is possible to immediately identify whether or not the informationrecording/recording unit 141 exists in the data lead-out area DTLDOmerely by decoding this area type information 935. Thus, asimplification and high speed access control can be made. As describedabove, identification information on the data lead-out area DTLDO isprovided by data ID internal setting of the terminator area TRM, therebymaking it easy to detect the terminator area TRM.

As a specific example, in the case where the border out area BRDO is setas an attribute of the data lead-out area NDTLDO (that is, in the casewhere the area type information 935 contained in the data ID of a dataframe in the border out BRDO is set to “10b”), the setting of thisterminator area TRM is not provided. Therefore, when the terminator areaTRM is recorded, the area having an attribute of the data lead-out areaNDTLDO, this terminator area TRM is regarded as part of the datalead-out area NDTLDO, thus disabling recording into the data area DTA.As a result, as in FIG. 16C, a user disable area 911 may remain.

In the present embodiment, the size of the terminator area TRM ischanged depending on a location on a write-once type information storagemedium, thereby reducing a finalization time and achieving efficientprocessing. This terminator area TRM indicates an end position ofrecording data. In addition, even in the case where this area is used ina read-only apparatus, which carries out track shift detection inaccordance with a DPD technique, the terminator area, is utilized toprevent overrun due to a track shift. Therefore, a width in a radialdirection on the write-once type information storage medium having thisterminator area TRM (width of a portion padded with the terminator areaTRM) must be a minimum of 0.05 nm or more because of the detectioncharacteristics of the read-only apparatus. A length of one cycle on thewrite-once type information storage medium is different depending on aradial position, and thus, the number of physical segment blocksincluded in one cycle is also different depending on the radialposition. Thus, the size of the terminator area TRM is differentdepending on the physical sector number of a physical sector which ispositioned at the beginning of the terminator area TRM, and the size ofthe terminator area TRM increases as the physical sector go to the outerperiphery side. A minimum value of a physical sector number of anallowable terminator area TRM must be greater than “04FE00h”. Thisderived from a restrictive condition in which the first bordered areaDRDA #1 is composed of 4080 or more physical segment blocks, making itnecessary for the first bordered area BRDA #1 to have a width equal toor greater than 1.0 mm in a radial direction on the write-once typeinformation storage medium. The terminator area TRM must start from aboundary position of physical segment blocks.

In FIG. 16D, a location in which each item of information is to berecorded is set for each physical segment block size for the reasondescribed previously, and a total of 64 KB user data recorded to bedistributed in 32 physical sectors is recorded in each physical segmentblock. A relative physical segment block number is set with respect to arespective one item of information, as shown in FIG. 16D, and the itemsof information are sequentially recorded in the write-once typeinformation storage medium in ascending order from the lowest relativephysical segment number. In the embodiment shown in FIGS. 16A to 16D,copies CRMD #0 to CRMD #4 of RMD, which are the same contents, areoverwritten five times in a copy information recording zone C_TRZ of thecontents recorded in the recording management zone shown in FIG. 17D.The reliability at the time of reproduction is improved by carrying outsuch overwriting, and, even if dust or scratch adheres onto a write-onceinformation storage medium, the copy information CRMD on the contentsrecorded in the recording management zone can be stably reproduced.Although the border end mark STB shown in FIG. 16D coincides with aborder end mark STB shown in FIG. 17D, the embodiment shown in FIG. 16Ddoes not have the mark NBM indicating a next border, unlike theembodiment shown in FIG. 17D. All the information on the main datacontained in reserved areas 901 and 902 is set to “00h”.

At the beginning of the border-in area BRDI, information which iscompletely identical to updated physical format information U_PFI ismultiply written six times from N+1 to N+6, configuring the updatedphysical format information U_PFI shown in FIG. 17D. The thus updatedphysical format information U_PFI is multiply written, thereby improvingthe reliability of information.

In FIG. 16D, the present embodiment is featured in that the recordingmanagement zone RMZ in the border zone is provided in the border-in areaBRDI. As shown in FIG. 15A, the size of the recording management zoneRMZ contained in the data lead-in area DTLDI is comparatively small. Ifthe setting of a new bordered area BRDA is frequently repeated, therecording management data RMD recorded in the recording management zoneRMZ is saturated, making it impossible to set a new bordered area BRDAmidway. As in the embodiment shown in FIG. 16D, there is attainedadvantageous effect that a recording management zone for recording therecording management data RMD relating to the bordered area BRDA #3 thatfollows is provided in the border-in area DRDI, whereby the setting of anew bordered area BRDA can be provided a number of times and theadditional writing count in the bordered area BRDA can be significantlyincreased. In the case where the bordered area BRDA #3 that follows theborder-in area BRDI including the recording management zone RMZ in thisborder zone is closed or in the case where the data area DTA isfinalized, it is necessary to repeatedly record all the last recordingmanagement data RMD into a spare area 273 established in an unrecordedstate in the recording management zone RMZ, and pad all the spare areawith the data. In thins manner, the spare area 273 in an unrecordedstate can be eliminated, a track shift (due to DPD) at the time ofreproduction in a read-only apparatus can be prevented, and thereproduction reliability of the recording management data RMD can beimproved by multiple recording of the recording management data. All thedata contained in a reserve area 903 are set to “00h”.

Although the border out area BRDO serves to prevent overrun due to atrack shift in the read-only apparatus while the use of DPD is presumed,there is no need for the border-in area BRDI to have a particularlylarge size other than having the updated physical format informationUPFI and the information contained in recording management zone RMZ inthe border zone. Therefore, an attempt is made to reduce the size to theminimum in order to reduce a time (required for border zone BRDZrecording) at the time of setting a new bordered area BRDA. With respectto FIG. 16A, before forming the border out area BRDO due to borderclosing, there is a high possibility that the user data additionalwriting enable range 205 is sufficiently large, and a large number ofadditional writing is carried out. Thus, it is necessary to largely takea value of “M” shown in FIG. 16D so that recording management data canbe recorded a number of times in the recording management zone RMZ in aborder zone. In contrast, with respect to FIG. 16B, in a state thatprecedes border closing of the bordered area BRDA #2 and that precedesrecording the border out area BRDO, the user data additional writingenable range 205 narrows, and thus, it is considered that not the numberof additional writings of the recording management data to beadditionally written in the recording management zone RMZ in the borderzone does not increase so much. Therefore, the setting size “M” of therecording management zone RMZ in the border-in area BRDI thatimmediately precedes the bordered area BRDA #2 can be taken to berelatively small. That is, as a location in which the border-in areaBRDI is arranged goes to the inner periphery side, the number ofpredicted additional writings of the recording management dataincreases. As the location goes to the outer periphery, the number ofpredicted additional writings of the recording management datadecreases. Thus, the present embodiment is featured in that the size ofthe border-in area BRDI is reduced. As a result, the reduction of a timefor setting a new bordered area BRDA and processing efficiency can beachieved.

A logical recording unit of the information recorded in the borderedarea BRDA shown in FIG. 17C is referred to as an R zone. Therefore, onebordered area BRDA is composed of at least one or more R zones. In acurrent DVD-ROM, as a file system, there are employed a file systemcalled a “UDF bridge” in which both of file management information whichconforms with a UDF (Universal Disc Format) and file managementinformation which conforms with ISO 9660 are recorded in one informationstorage medium at the same time. In a file management method whichconforms to ISO 9660, there is a rule that one file must be continuouslyrecorded in an information storage medium. That is, informationcontained in one file is disabled to be divisionally arranged at adiscrete position on an information storage medium. Therefore, forexample, in the case where information has been recorded in conformancewith the above UDF bridge, all the information configuring one file iscontinuously recorded. Thus, it is possible to adapt this area in whichone file is continuously recorded so as to configure one R zone.

FIGS. 18A to 18D show a data structure in the control data zone CDZ andthe R-physical information zone RIZ. As shown in FIG. 18B, physicalformat information (PFI) and disc manufacturing information (DMI) existin the control data zone CDZ, and similarly, an DMI (Disc ManufacturingInformation) and R PFI (R-Physical Format Information) are contained inan R-physical information zone RIZ.

Information 251 relating to a medium manufacture country and mediummanufacturer's nationality information 252 are recorded in mediummanufacture related information DMI. When a commercially availableinformation storage medium infringes a patent, there is a case in whichan infringement warning is supplied to such a country in which amanufacturing location exists or an information storage medium isconsumed (or used). A manufacturing location (country name) isidentified by being obliged to record the information contained in aninformation storage medium, and a patent infringement warning is easilysupplied, whereby an intellectual property is guaranteed, and technicaladvancement is accelerated. Further, other medium manufacture relatedinformation 253 is also recorded in the medium manufacture relatedinformation DMI.

The present embodiment is featured in that type of information to berecorded is specified depending on a recording location (relative byteposition from the beginning) in physical format information PFI orR-physical format information R PFI. That is, as a recording location inthe physical format information PFI or R-physical format information RPFI, common information 261 in a DVD family is recorded in an 32-bytearea from byte 0 to byte 31; common information 262 in an HD DVD familywhich is the subject of the present embodiment is recorded in 96 bytesfrom byte 32 to byte 127; unique information (specific information) 263relating to various specification types or part versions are recordingin 384 bytes from byte 128 to byte 511; and information corresponding toeach revision is recorded in 1536 bytes from byte 512 to byte 2047. Inthis way, the information allocation positions in the physical formatinformation are used in common depending on the contents of information,whereby the locations of the recorded information are used in commondepending on medium type, thus making it possible to carry out in commonand simplify a reproducing process of an information reproducingapparatus or an information recording/reproducing apparatus. The commoninformation 261 in a DVD family recorded in byte 0 to byte 31, as shownin FIG. 18D, is divided into: information 267 recorded in common in allof a read-only type information storage medium and a rewritable-typeinformation storage medium, and a write-once type information storagemedium recorded from byte 0 to byte 16; and information 268 which isrecorded in common in the rewritable-type information storage medium andthe write-once type information storage medium from byte 17 to byte 31and which is not recorded in the read-only type medium.

Now, a description will be given with respect to the significance ofspecific information 263 of the type and version of each of thespecifications from byte 128 to byte 511 shown in FIG. 18C and thesignificance of information content 264 which can be set specific toeach of the revisions from byte 512 to byte 2047. That is, in thespecific information 263 of type and version of each of thespecifications from byte 128 to byte 511, the significance of thecontents of recording information at each byte position coincides with arewritable-type information storage medium of a different typeregardless of a write-once type information storage medium. Theinformation content 264 which can be set specific to each of therevisions from byte 512 to byte 2047 permits the fact that if a revisionis different from another in the same type of medium as well as adifference between a rewritable-type information storage medium and awrite-once type information storage medium whose types are differentfrom each other, the significances of the contents of recordinginformation at byte positions are different from each other.

A specific method for mounting an information recording/reproducingapparatus will be described below. The specification (version book) orrevision book describe both of the reproduction signal characteristicsderived from the “H-L” recording film and the reproduction signalcharacteristics derived from the “L-H” recording film. Concurrently, thecorresponding circuits are provided on a two by two basis in the PRequalizing circuit 130 and Viterbi decoder 156 shown in FIG. 8. When aninformation storage medium is mounted in the information reproductionunit 141, first, the slice level detector circuit 132 for reading theinformation contained in the system lea-in area SYLDI is started up.This slice level detector circuit 132 reads information on polarity of arecording mark recorded in this 192 byte (identification of “H-L” or“L-H”); and then make judgment of “H-L” or “L-H”. In response to thejudgment, after the PR equalizing circuit 130 and a circuitry containedin the Viterbi decoder 156 has been switched, the information recordedin the data lead-in area DTLDI or data area DTA is reproduced. The abovedescribed method can read the information contained in the data lead-inarea DTLDI or data area DTA comparatively quickly, and moreover,precisely. Although revision number information defining a maximumrecording speed is described in byte 17 and revision number informationdefining a minimum recording speed is described in byte 18, these itemsof information are merely provided as range information defining amaximum and a minimum. In the case where the most stable recording iscarried out, there is a need for optimal line speed information at thetime of recording, and thus, the associated information is recorded inbyte 193.

The present embodiment is featured in that information on a rimintensity value of an optical system along a circumferential directionof byte 194 and information on a rim intensity value of an opticalsystem along in a radial direction of byte 195 is recorded as opticalsystem condition information at a position which precedes information ona variety of recording conditions (write strategies) included in theinformation content 264 set specific to each revision. These items ofinformation denote conditional information on an optical system of anoptical head used when identifying a recording condition arranged at theback side. The rim intensity used here denotes a distribution state ofincident light incident to an objective lens before focusing on arecording surface of an information storage medium. This intensity isdefined by a strength value at a peripheral position of an objectivelens (iris face outer periphery position) when a center intensity of anincident light intensity distribution is defined as “1”. The incidentlight intensity distribution relevant to an objective lens is notsymmetrical on a point to point basis; an elliptical distribution isformed; and the rim intensity values are different from each otherdepending on the radial direction and the circumferential direction ofthe information storage medium. Thus, two values are recorded. As therim intensity value increases, a focal spot size on a recording surfaceof the information storage medium is reduced, and thus, an optimalrecording power condition changes depending on this rim intensity value.The information recording/reproducing apparatus recognizes in advancethe rim intensity value information contained in its own optical head.Thus, this apparatus reads the rim intensity values of the opticalsystem along the circumferential direction and the radial direction, thevalue being recorded in the information storage medium, and comparesvalues of its own optical head. If there is no large difference as aresult of the comparison, a recording condition recorded at the backside can be applied. If there is a large difference, there is a need forignoring the recording condition recorded at the back side and startingidentifying an optimal recording condition while therecording/reproducing apparatus carries out test writing by utilizingthe drive test zone DRTZ.

Therefore, there is a need for quickly making a decision as to whetherto utilize the recording condition recorded at the back side or whetherto start identifying the optimal recording condition while ignoring theinformation and carrying out test writing by oneself. There is attainedadvantageous effect that the rim intensity information can be read, andthen judgment can be made at a high speed as to whether or not therecoding condition arranged later is met by arranging conditionalinformation on an optical system identified at a preceding position withrespect to a position at which the recommended recording condition hasbeen recorded.

As described above, according to the present embodiment, there aredivisionally provided: a specification (version book) in which a versionis changed when the contents have been significantly changed; and arevision book in which the corresponding revision is changed and issued,and only a revision book is issued, the book having updated onlyrevision every time a recording speed is improved. Therefore, if arevision number is different from another, a recording condition in arevision book changes. Thus, information relating to a recordingcondition (write strategy) is mainly recorded in the information content264 which can be set specific to each of the revisions from byte 512 tobyte 2047. The information content 264 which can be set specific to eachof the revisions from byte 512 to byte 2047 permits the fact that if arevision is different from another in the same type of medium as well asa difference between a rewritable-type information storage medium and awrite-once type information storage medium whose types are differentfrom each other, the significances of the contents of recordinginformation at byte positions are different from each other.

In a write-once type information storage medium, with respect toR-physical format information recorded in an R-physical information zoneRIZ contained in the data lead-in area DTLDI, border zone start positioninformation (first border outermost periphery address) is added to thephysical format information PFI (copy of HD DVD family commoninformation), and the added information is described. In the updatedphysical format information U_PFI, updated in the border-in area BRDIshown in FIGS. 17A to 17D or FIGS. 16A to 16D, start positioninformation (self-border outermost periphery address) is added to thephysical format information (copy of HD DVD family common information),and the added information is recorded. The updated start positioninformation is arranged in byte 256 to byte 263 which are positionssucceeding information relating to a recording condition such as peakpower or bias power 1 (information content 264 which can be set specificto each revision), the position following the common information 262contained in the DVD family.

With respect to the specific contents of information relating to theborer zone start position information, the start position information onthe border out area BRDO situated at the outside of the (current)bordered area BRDA currently used in byte 256 to byte 259 is describedin PSN (Physical Sector Number); and border-in area BRDI start positioninformation relating to the bordered area BRDA to be used next isdescribed in the physical sector number (PSN) in byte 260 to byte 263.

The specific contents of information relating to the updated startposition information indicate the latest border zone positioninformation in the case where a bordered area BRDA has been newly set.The start position information on the border out area BRDO situated atthe outside of the (current) bordered area BRDA currently used in byte256 to byte 259 is described in PSN (Physical Sector Number); and thestart position information on the border-in area BRDI relating to thebordered area BRDA to be used next is described in the sector number(PSN) in byte 260 to byte 263. In the case where recording cannot becarried out in the next bordered area BRDA, this area (ranging from byte260 to byte 263) is padded with all “00h”.

In contrast, the R-physical format information RPFI contained in thewrite-once type information storage medium records the end positioninformation on the recorded data contained in the corresponding borderedarea BRDA.

Further, the read only type information storage medium records the endaddress information contained in “Layer 0” which is a front layer whenseen from the reproduction optical system; and the rewritable-typeinformation storage medium records information on a differential valueof each item of start position information between a land area and agroove area.

As shown in FIG. 17D, the associated copy information exists in theborder-out zone BRDO as copy information C RMZ indicating the contentsrecorded in the recording management zone. This recording managementzone RMZ records RMD (Recording Management Data) having the same datasize as one physical segment block size, as shown in FIG. 15B, so thatnew recording management data RMD updated every time the contents of therecording management data RMD is updated can be sequentially addedbackwardly. The recording management data RMD is further divided intofine RMD field information RMDF of 2048 byte size. The first 2048 bytesin the recording management data are provided as a reserved area.

In the information reproducing apparatus or informationrecording/reproducing apparatus shown in FIG. 8, a wobble signaldetecting section 135 is used for track shift detection using apush-pull signal. In the track shift detecting circuit (wobble signaldetecting section 135), as a value of the above push-pull signal(I1−I2)_(pp)/(I1+I2)_(DC), track shift detection can be stably carriedout in the range of 0.1≦(I1−I2)_(pp)/(I1+I2)_(DC)≦0.8. In particular,with respect to an “H-L” recording film, track shift detection can becarried out more stably in the range of 0.26(I1−I2)_(pp)/(I1+I2)_(DC)≦0.52; and with respect to a “L-H” recordingfilm, track shift detection can be carried out more stably in the rangeof 0.30≦(I1−I2)_(pp)/(I1+I2)_(DC)≦0.60.

Therefore, in the present embodiment, information storage mediumcharacteristics are defined so that a push-pull signal is included inthe range of 0.1≦(I1−I2)_(pp)/(I1+I2)_(DC)≦0.8 (preferably, in the rangeof 0.26≦(I1−I2)_(pp)/(I1+I2)_(DC)≦0.52 with respect to the “H-L”recording film and in the range of 0.30≦(I1−I2)_(pp)/(I1+I2)_(DC)≦0.60with respect to the “L-H” recording film. The above range is defined soas to be established in both of a recorded location in data lead-in areaDTLDI or data area DTA and data lead-out area DTLDO (location in which arecording mark exists) and an unrecorded location (location in which norecording mark exists). However, in the present embodiment, withoutbeing limited thereto, this range can be defined so as to be establishedin only the recorded location (location in which a recording markexists) or in only the unrecorded location (location in which norecording mark exists). Further, in the present embodiment, as a ratioof amplitudes (I1−I2)_(pp) after and (I1−I2)_(pp before) of an (I1−I2)signal in the recorded location and in the unrecorded location, theinformation storage medium characteristics are defined so as to meet0.7≦(I1−I2)_(pp after)/(I1−I2)_(pp before)≦1.50 regardless of the “H-L”recording film or the “L-H” recording film, whichever may be used. Thevalues of the track shape and the push-pull signal amplitude describedin the least significant 7 bits within the push-pull signal amplitudeare displayed by percentage relevant to an actual push-pull signalamplitude value. For example, in the case where the amplitude of thepush-pull signal is 0.70 (70%), 0.7= 70/100 is obtained. Thus, as thedata described in this field, information “0100 0110b” is described, theinformation expressing a decimal value of “70” in binary notation.

In the case of a write-once type information recording medium, trackingis carried out on a pre-groove area (a recording mark is formed on thepre-groove area). Thus, this on-track signal denotes a detection signallevel when tracking is carried out on the pre-groove area. That is, theabove-described on-track information denotes a signal level(Iot)_(groove) of an unrecorded area when a track loop shown in FIG.27B, for example is turned ON. The present invention allows therecording mark to be formed on an area between the pre-grooves. In thiscase, the “land” can be regarded as “groove.”

In R physical format information RPFI, a physical sector number(030000h) is recorded, the number representing the start positioninformation contained in the data area DTA. In addition, a physicalsector number is recorded, the number indicating a location in whichlast recording has been made in the last R zone included in the borderedarea.

In updated physical format information UPFI, there are recorded: aphysical sector number (030000h) representing the start positioninformation contained in the data area DTA; and a physical sector numberindicating a location in which last recording has been made in the lastR zone included in the bordered area.

These items of positional information can be described in ECC blockaddress numbers according to another embodiment instead of beingdescribed in physical sector numbers. As described later, in the presentembodiment, one ECC block is composed of 32 sectors. Therefore, theleast significant five bits of the physical sector number of a sectorarranged at the beginning in a specific ECC block coincides with that ofa sector arranged at the start position in the adjacent ECC block. Inthe case where a physical sector number has been assigned so that theleast significant five bits of the physical sector of the sectorarranged at the beginning in the ECC block is “00000”, the values of theleast significant six bits or more of the physical sector numbers of allthe sectors existing in the same ECC block coincide with each other.Therefore, address information obtained by eliminating the leastsignificant five bit data of the physical sector numbers of the sectorsexisting in the same ECC block as above and sampling only data of theleast significant six bit and subsequent is defined as ECC block addressinformation (or ECC block address number). As described later, the datasegment address information (or physical segment block numberinformation) recorded in advance by wobble modulation coincides with theabove ECC block address. Thus, when the positional information containedin the recording management data RMD is described in the ECC blockaddress numbers, there is attained advantageous effects described below:

1) An access to an unrecorded area is accelerated in particular:

A differential calculation process is facilitated because a positionalinformation unit of the recording management data RMD coincides with aninformation unit of data segment addresses recorded in advance by wobblemodulation; and

2) A management data size in the recording management data RMD can bereduced:

The number of bits required for describing address information can bereduced by 5 bits per address.

As described later, a single physical segment block length coincideswith a one data segment length, and the user data for one ECC block isrecorded in one data segment. Therefore, an address is expressed as an“ECC block address number”; an “ECC block address”; a “data segmentaddress”, a “data segment number”, or a “physical segment block number”and the like. These expressions have the same meaning.

In the allocation position information on the recording management dataRMD existing in RMD field 0, size information in that the recordingmanagement zone RMZ capable of sequentially additionally writing therecording management data RMD is recorded in ECC block units or inphysical segment block units. As shown in FIG. 15B, one recordingmanagement zone RMD is recorded on one by one physical segment blockbasis, and thus, based on this information, it is possible to identifyhow many times the updated recording management data RMD can beadditionally written in the recording management zone RMZ. Next, acurrent recording management data number is recorded in the recordingmanagement zone RMZ. This denotes number information on the recordingmanagement data RMD which has been already recorded in the recodingmanagement zone RMZ. For example, assuming that this informationcorresponds to the information contained in the recording managementdata RMD #2 as an example shown in FIG. 15B, this informationcorresponds to the second recorded recording management data RMD in therecoding management zone RMZ, and thus, a value “2” is recorded in thisfield. Next, the residual amount information contained in the recordingmanagement zone RMZ is recorded. This information denotes information onthe item number of the recording management data RMD which can befurther added in the recording management zone RMZ, and is described inphysical segment block units (=ECC block units=data segment units).Among the above three items of information, the following relationshipis established.

[Size information having set RMZ therein]=[Current recording managementdata number]+[residual amount in RMZ]

The present embodiment is featured in that the use amount or theresidual amount information on the recording management data RMDcontained in the recording management zone RMZ is recorded in arecording area of the recording management data RMD.

For example, in the case where all information is recorded in onewrite-once type information storage medium once, the recordingmanagement data RMD may be recorded only once. However, in the casewhere an attempt is made to repeatedly record additional writing of theuser data (additional writing of the user data in the user dataadditional writing enable range 205) very finely in one write-once typeinformation storage medium, it is necessary to additionally writerecording management data RMD updated every time additional writing iscarried out. In this case, if the recording management data RMD isfrequently additionally written, the reserved area 273 shown in FIG. 15Bis eliminated, and the information recording/reproducing apparatusrequires countermeasures against this elimination. Therefore, the useamount or residual amount information on the recording management dataRMD contained in the recording management zone RMZ is recorded in arecording area of the recording management data RMD, thereby making itpossible to identify in advance a state in which additional writing inthe recording management zone RMZ cannot be carried out and to takeaction by the information recording/reproducing apparatus earlier.

A description will be given with respect to an example of a processingmethod for newly setting an extended drive test zone EDRTZ by theinformation recording/reproducing apparatus shown in FIG. 8 and carriedout test writing in the zone.

1) A write-once type information storage medium is mounted on aninformation recording/reproducing apparatus.

2) Data formed in the burst cutting area BCA is reproduced by theinformation recording/reproducing unit 141; the recorded data issupplied to the control unit 143; and the information is decoded in thecontrol unit 143, and it is determined whether or not processing canproceeds to a next step.

3) Information recorded in the control data zone CDZ in the systemlead-in area SYLDI is reproduced by the informationrecording/reproducing unit 141, and the reproduced information istransferred to the control unit 143.

4) Values of rim intensities when a recommended recording condition hasbeen identified in the control unit 143 are compared with a value of rimintensity of an optical head used at the informationrecording/reproducing unit 141; and an area size required for testwriting is identified.

5) The information contained in recording management data is reproducedby the information recording/reproducing unit 141, and the reproducedinformation is transferred to the control unit 143. The control sectiondecodes the information contained in the RMD field 4 and determineswhether or not there is a margin of an area size required for testwriting, the size being identified in step (4). In the case where thejudgment result is affirmative, processing proceeds to step (6).Otherwise, processing proceeds to step (9).

6) A location for starting test writing is identified based on endposition information on a location which has already been used for testwriting in the drive test zone DRTZ or extended drive test zone EDRTZused for test writing from the RMD field 4.

7) Test writing is executed by the size identified in step (4) from thelocation identified in step (6).

8) The number of locations used for test writing has been increased inaccordance with the processing in step (7), and thus, recordingmanagement data RMD obtained by rewriting the end position informationon the locations which has already been used for test writing istemporarily stored in the memory unit 175, and processing proceeds tostep (12).

9) The information recording/reproducing unit 141 reads information on“end position of the latest user data recording enable range 205”recorded in the RMD field 0 or “end position information on the userdata additional writing enable range” recorded in the allocationlocation information on the data area DTA contained in the physical; andthe control unit 143 further internally sets the range of a newly setextended drive test zone EDRTZ.

10) Information on “end position of the latest used data recordingenable range 205” recorded in the RMD field 0 based on the resultdescribed in step (9) is updated and additional setting countinformation on the extended drive test zone EDRTZ contained in the RMDfield 4 is incremented by one (that is, the count is added by 1); andfurther, the memory unit 175 temporarily stores the recording managementdata RMD obtained by adding the start/end position information on thenewly set extended drive test zone EDRTZ.

11) Processing moves from step (7) to (12).

12) Required user information additionally written into the user dataadditional writing enable range 205 under an optimal recording conditionobtained as a result of test writing carried out in step (7).

13) The memory unit 175 temporarily stores the recording management dataRMD updated by additionally writing the start/end position informationcontained in an R zone which has been newly generated in response tostep (12).

14) The control unit 143 controls the information recording/reproducingunit 141 to additionally record the latest recording management data RMDtemporarily stored in the memory unit 175, in the reserved area 273 (forexample, FIG. 15B) contained in the recording management zone RMZ.

The information on the physical sector number or the physical segmentnumber (PSN) indicating the lastly recorded position in the write-onceinformation storage medium shown in the present embodiment can beobtained from the information contained in the “recording positionmanagement data RDM lastly recorded in the extended recording managementzone RMZ that has been lastly set”. That is, the recording positionmanagement data RMD includes end position information on an n-th“complete type R zone (Complete R zone)” described in RMD field 7 orlater or information on “physical sector number LRA representing thelast recording position in the n-th R zone” shown in, thereby readingthe physical sector number or physical segment number (PSN) in thelastly recorded location from the inside of the recording positionmanagement data RMD (refer to RMD #3 shown in FIG. 15B, for example)that has been lastly recorded in the lastly set extended RMZ, and makingit possible to know the lastly recorded location from a result of thereading.

The information reproducing apparatus uses a DPD (Differential PhaseDetection) technique instead of a Push-Pull technique for track shiftdetection, and thus, tracking control can be carried out only in an areain which an emboss pit or a recording mark exists. Thus, the informationreproducing apparatus cannot provide an access to an unrecorded area ofthe write-once type information storage medium, making it impossible tocarry out reproduction in the RMD duplication zone RDZ that includes theunrecorded area. Thus, the recording position management data RMDrecorded therein cannot be reproduced. Instead, the informationreproducing apparatus can reproduce physical format information PFI, Rphysical information zone R-PFIZ, and updated physical formatinformation UPFI. Thus, a search can be made for the lastly recordedlocation.

The information reproducing apparatus carries out informationreproduction in a system lead-in area SYLDI, and then, reads the lastpositional information on the existing information data recorded in theR physical information zone R-PFIZ (information on “physical sectornumber indicating the lastly recorded location in the last R zone in thecorresponding border-in area”). As a result, it is possible to know thelast location of the bordered area BRDA #1. In addition, after checkinga position of border-out BRDO allocated immediately after the lastlocation, it is possible to read information on the updated physicalformat UPFI recorded in border-in BRDI recorded immediately after thechecked position.

Instead of the foregoing method utilizing “physical sector numberindicating the lastly recorded location in the last R zone in thecorresponding border-in area” described in FIG. 19, an access may beprovided to the start position of border-out BRDO by using informationon “physical sector number PSN indicating a start position of a borderzone” described in the 256th to 263rd bytes (this start position denotesthe start position of border-out BRDO, as is evident from FIG. 16C).

Next, an access is provided to the last position of recorded data,thereby reading the last position information (FIG. 19) on the recordeddata contained in updated physical format information UFPI. A processingoperation of reading “information on the lastly recorded physical sectornumber or physical segment number (PSN)” recorded in the updatedphysical format information, and then, providing access to the lastlyrecorded physical sector number or physical segment number (PSN) basedon the read information is repeated until the lastly recorded physicalsector number PSN in the last R zone has been reached. That is, it isdetermined that a location of reading information, the location havingbeen reached after access is really the lastly recorded position in thelast R zone. In the case where the determination result is negative, theabove-described access processing operation is repeated. As in Rphysical information zone R-PFIZ, in the present embodiment, a searchmay be made for recording position of the updated physical formatinformation UPFI recorded in a border zone (border-in BRDI) by utilizinginformation on the updated physical sector number or physical segmentnumber (PSN) indicating a start position of a border zone” in theupdated physical format information UPFI.

When the position of the physical sector number (or physical segmentnumber) lastly recorded in the last R zone is found, the informationreproducing apparatus carries out reproduction from the immediatelypreceding position of border-out. Then, the lastly recorded position isreached while the inside of the last bordered area BRDA is seriallyreproduced from the start. Then, a check of the last border-out BRDO ismade. In the write-once type information storage medium according to thepresent embodiment, at the outside of the above last border-out BRDO, anunrecorded area in which no recording mark is recorded follows up to theposition of data lead-out DTLDO. In the information reproducingapparatus, no tracking is carried out in an unrecorded area on thewrite-once type information recording medium, and the information on thephysical sector number PSN is not recorded, thus making it impossible tocarry out reproduction at a position following the last border-out BRDO.Thus, when the last border-out position has been reached, an accessprocessing operation and a continuous reproducing processing operationterminate.

Referring to FIG. 19, a description will be given with respect to atiming (updating condition) of updating the contents of information inthe recording position management data RMD. There exist five types ofconditions for updating information on the recording position managementdata RMD.

(Condition 1a) In the case where medium status information (Disc states)in RMD field “0” is changed:

An update processing operation of the recording position management dataRMD is not carried out at the time of recording of a terminator (“endposition information” recorded at the rear (outer periphery side) of thelastly recorded border-out BRDO).

(Condition 1b) In the case where an inner test zone address or an outertest zone address (Inner or outer test zone address) specified in RMDfield “1” is changed:

(Condition 2) In the case where border-out BRDO start positioninformation (Start Physical Sector Number of Border-out area) or open(write-once possible) recording management zone RMZ number (openExtended RMZ number), specified in RMD field “3” is changed:

(Condition 3) In the case where information on any one of the followingitems is changed in RMD filed “4”:

1) A total number of unspecified R zone number, open type R zone number,and complete type R zone or invisible R zone number (Invisible R Zonenumber)

2) First open type R zone number information (First Open R Zone number)

3) Second open type R zone number information (Second R Zone number)

In the present embodiment, during a period in which a series ofinformation recording operations are made for a write-once typeinformation storage medium such as HD DVD-R (by means of a disc drive),there is no need for updating RMD. For example, in the case of recordingvideo image information, there is a need for continuous recording to beguaranteed. If access control of up to a position of recordingmanagement data RMD is made in order to update recording positionmanagement data RMD in the middle of video image information recording(image recording), continuous recording is not guaranteed becauserecording of video image information is interrupted. Therefore, theupdate of RMD is generally carried out after the video image recordingis terminated. If a series of video image information recordingoperations continues for an excessively long period of time, thelocation lastly recorded on the write-once type information storagemedium at the current time point and the last position informationcontained in the recording position management data RMD that has beenalready recorded in the write-once type information storage medium willbe significantly shifted. At this time, in the case where an abnormalphenomenon in the middle of continuous recording occurs, and then, theinformation recording/reproducing apparatus (disc drive) is forciblyterminated, discrepancy between “the last position information containedin the recording position management data RMD” and a recording positionimmediately before forcible termination becomes excessively large. As aresult, there occurs a danger that data recovery conforming to arecording position immediately before forcible termination with respectto the “last position information contained in the recording positionmanagement data RMD” becomes difficult. Therefore, in the presentembodiment, the following update condition is further added.

(Condition 4) (Information on the recording position management data RMDis updated) in the case where discrepancy (a differential result of“PSN−LRA”) between a “physical sector number LRA indicating the lastrecording position in an R zone” recorded in the latest recordingposition management data RMD and a “physical sector number PSN in thelastly recorded location in a R zone at the current time point” whichserially changes during continuous recording exceeds 8192:

However, in the above-described “condition 1b)” or “(condition 4)”, noupdating is carried out in the case where the size of an unrecordedlocation in the recording management zone RMZ (reserved area 273) isequal to or smaller than 4 physical segment blocks (4×64 KB).

Now, a description will be given with respect to an extended recordingmanagement zone. As setting locations of the recording management zone,the present embodiment defines the following three types.

1) Recording Management Zone RMZ (L-RMZ) in Data Lead-In Area DTLDI

As is evident from FIG. 16B, in the present embodiment, part of theinside of the data lead-in area DTLDI is used for the border-in BRDIcorresponding to the first bordered area. Therefore, the recodingposition management zone RMZ to be recorded in the border-in BRDI thatcorresponds to the first bordered area is preset in the data lead-inarea DTLDI, as shown in FIG. 15A. In the internal structure of thisrecording management zone RMZ, serial recording position management dataRMD can be written once by 64 Kbytes (by 1 physical segment block size).

2) Recording Management Zone RMZ (B-RMZ) in Border-In BRDI

In the write-once type information storage medium according to thepresent embodiment, before reproducing recorded information by areproduction only apparatus, there is a need for a border closeprocessing operation. In the case where new information is recordedafter a border has been closed once, there is a need for setting a newbordered area BRDA. The border-in BRDI is set at a position precedingthis new bordered area BRDA. The unrecorded area in the latest recordingmanagement zone is closed at the stage of border close processingoperation (reserved area 273 shown in FIG. 15B). Thus, there is a needfor setting a new area (recording management zone RMZ) for recording therecording position management data RMD that indicates a position of theinformation recorded in a new bordered area BRDA. The presentembodiment, as shown in FIG. 16D, is featured in that a recordingmanagement zone RMZ is set in the newly set border-in BRDI. The internalstructure of the recording management zone RMZ in this border zone has astructure that is completely identical to the “recording management zoneRMZ (L-RMZ) that corresponds to the first bordered area”. In addition,the information contained in the recording position management data RMDrecorded in this area is recorded together with recording positionmanagement information relating to the data recorded in the precedingbordered area BRDA as well as the recording position management datarelating to the data recorded in the corresponding bordered area BRDA.

3) Recording Management Zone RMZ (U-RMZ) in Bordered Area BRDA

RMZ in border-in BRDI (B-RMZ), shown in the item (2) cannot be setunless a new bordered area BRDA is set. In addition, the size of thefirst bordered area management zone RMZ (L-RMZ) shown in the item (1) isfinite, a reserved area 273 is depleted while additional-writing isrepeated, and new recording position management data RMD cannot bewritten. In order to solve the above-described problem, in the presentembodiment, an R zone for recoding a recording management zone RMZ isnewly provided in a bordered area BRDA so as to enable further addition.That is, there exists a specific R zone in which the recordingmanagement zone RMZ (U-RMZ) in the bordered area BRDA” is set.

In addition, without being limited to a case of reducing the remainingsize of an unrecorded area (reserved area 273) in the first borderedarea management zone RMZ (L-RMZ), the present embodiment is featured inthat, in the case of reducing the remaining size of the unrecorded area(reserved area 273) in the “recording management zone RMZ (B-RMZ) in theborder-in BRDI” and in the “recording management zone RMZ (U-RMZ) in thebordered area BRDA” that has already been set, the above-described“recording management zone RMZ (U-RMZ) in the bordered area BRDA” can beset.

The contents of information recorded in the recording management zoneRMZ (U-RMZ) in this bordered area BRDA have a structure that iscompletely identical to that in the recording management zone RMZ(L-RMZ) in the data lead-in area DTLDI shown in FIG. 15B. In addition,the information contained in the recoding position management data RMDrecorded in this area is recorded together with recording positionmanagement information relating to the data recorded in the precedingbordered area BRDA as well as the recoding position management datarelating to the data recorded in the corresponding bordered area BRDA.

Among the variety of recording management zones RMZ described above,

1) A position of the recording management zone RMZ (L-RMZ) in the datalead-in area DTLDI is preset before recording user data.

However, in the present embodiment,

2) A recording management zone RMZ (B-RMZ) in the border-in BRDI; and

3) A recording management zone RMZ (U-RMZ) in the bordered area BRDA

are properly set (extensively provided) by the informationrecording/reproducing apparatus in accordance with a user data recording(additional write) state, and thus, these zones are referred to as“extended (type) recording management zones RMZ”.

In the case where an unrecorded area in a currently used recordingmanagement zone RMZ (reserved area 273) is equal to or smaller than aphysical sector block (15×64 KB), the setting of the recordingmanagement zone RMZ (U-RMZ) in the bordered area BRDA can be provided.The size of the recording management zone RMZ in the bordered area BRDAat the time of setting (U-RMZ) is defined as the size (128×64 KB) of 128physical segment blocks, and this size is defined as an R zone usedexclusively for the recording management zone RMZ.

In the write-once type information storage medium according to thepresent embodiment, it becomes possible to set the above-described threetypes of recording management zones RMZ, and thus, the presence of avery large number of recording management zones RMZ is allowed on onewrite-once type information recording/storage medium. Therefore, in thepresent embodiment, for the purpose of facilitating a search for thelatest recording position management data RMD recording location, thefollowing processing operations are made:

1) In the case of newly setting a recording management zone RMZ, thelatest recording position management data RMD is overwritten in therecording management zone RMZ that has been used up to now so as not toallow an unrecorded area to exist in the recording management zone RMZthat has been used up to now. In this manner, it becomes possible toidentify whether a recording management zone is currently used or is setin a new location.

2) Every time a recording management zone RMZ is newly set, copyinformation 48 on the latest recording position management data RMD isrecorded in an RMD duplication zone RMZ. In this manner, a search iseasily made for the currently used recording management zone RMZlocation.

The presence of a large number of unrecorded areas is allowed in thewrite-once type information storage medium according to the presentembodiment. However, in a reproduction only apparatus, a DPD(Differential Phase Detection) technique is used for track shiftdetection, thus disabling tracking in an unrecorded area. Therefore,before reproducing the above described write-once type informationstorage medium by the reproduction only apparatus, there is a need forcarrying out a border close processing operation so that an unrecordedarea does not exist.

A detailed description will be given with respect to the patterncontents of a reference code recorded in the reference code recordingzone RCZ. In a current DVD standard, an “ 8/16 modulation” system forconverting 8-bit data to 16-channel bits is employed as a modulationsystem. As a pattern of a reference code serving as a channel bitpattern recorded in an information storage medium after modulated, thereis employed a repetition pattern “00100000100000010010000010000001”. Incomparison with this pattern, in the present embodiment, ETM modulationfor modulating 8-bit data into 12-channel bits is used, providing an RLL(1, 10) run length restriction. In addition, the PRML technique isemployed for signal reproduction from the data lead-in area DTLDI, dataarea DTA, data lead-out area DTLDO, and middle area MDA. Therefore,there is a need for setting the above described modulation rule and apattern of a reference code optimal for PRML detection. In accordancewith the RLL (1, 10) run length restriction, a minimum value ofcontinuous “0” settings is “d=1”, and is a repetition pattern of“10101010”. Assuming that a distance from a code “0” to the nextadjacent code is “T”, a distance relevant to the adjacent “1” in theabove pattern is obtained as “2T”. In the present embodiment, in orderto achieve high density of an information storage medium, as describedpreviously, a reproduction signal from the repetition pattern(“10101010”) of “2T” recorded on the information storage medium is closeto a shutdown frequency of MTF (Modulation Transfer Function)characteristics of an objective lens in an optical head (exists in theinformation recording/reproducing unit 141 shown in FIG. 8); and thus, adegree of modulation (signal amplitude) is hardly obtained. Therefore,in the case where a reproduction signal from a repetition pattern(“10101010”) of “2T” has been used as a reproduction signal used forcircuit tuning of the information reproducing apparatus or theinformation recording/reproducing apparatus (for example, initialing andoptimizing tap coefficients), noise effect is significant, andstabilization is poor. Therefore, with respect to a signal aftermodulated in accordance with RLL (1, 10) run length restriction, then,it is desirable to carry out circuit tuning by using a pattern of “3T”having high density.

In the case where a digital sum value (DSV) of the reproduction signalis considered, an absolute value of a DC (direct current) valueincreases in proportion to the number of continuous “0”s between “1” andnext “1” that immediately follows it, and the increased value is addedto the immediately preceding DSV value. The polarity of this added DCvalue is inverted every time “1” is reached. Therefore, as a method forsetting the DSV value to “0” where a channel bit pattern havingcontinuous reference code is followed, the DSV value is set to be “0” in12 channel bit patterns after ETM-modulated, whereby the degree offreedom in reference code pattern design is increased more significantlyby setting to an odd number the number of generated “1” appearing in 12channel bit patterns after ETM-modulated; offsetting a DC componentgenerated in one set of reference code cells consisting of a next set.Therefore, in the present embodiment, the number of “1” appearing in thereference code cells consisting of 12 channel bit patterns afterETM-modulated is set to an odd number.

In the present embodiment, in order to achieve high density, there isemployed a mark edge recording technique in which a location of “1”coincides with a boundary position of a recording mark or an emboss pit.For example, in the case where a repetition pattern of “3T”(“100100100100100100100”) is followed, there occurs a case in which alength of a recording mark or an emboss pit and a length of a spacebetween the mark and pit are slightly different from each otherdepending on a recording condition or an original master producingcondition. In the case where the PRML detecting technique has beenemployed, a level value of a reproduction signal becomes very important.As described previously, even in the case where the length of therecording mark or emboss pit and the length of the space between themark and pit are different from each other, there occurs a necessity ofcorrecting such slightly different component in a circuit manner so asto enable signal detection stably and precisely. Therefore, a referencecode for tuning a circuit constant has a space with a length of “3T”,like a recording mark or an emboss pit with a length of “3T”, therebyimproving the precision of tuning a circuit constant. Thus, if a patternof “1001001” is included as a reference code pattern according to thepresent embodiment, the recording mark or emboss pit having the length“3T”; and a space are always arranged.

In addition, circuit tuning also requires a pattern in a non-dense stateas well as a pattern (“1001001”) having a high density. Therefore, inconsideration of that fact that a non-dense state (pattern in which “0”is continuously and frequently generated) is generated at a portion atwhich a pattern of “1001001” has been excluded from among 12 channel bitpatterns after ETM-modulated and the number of generated “1”s is set inan odd number, with respect to a reference code pattern, a repetition of“100100100000” is obtained as an optical condition, as shown in FIGS.24A, 24B, 24C, and 24D. In order to ensure that the channel bit patternafter modulated is produced as the pattern, although not shown, there isa need for setting to “A4h” a data word before modulated, when utilizinga modulation table specified in an H format. This data on “A4h”(hexadecimal notation) corresponds to a data symbol “164” (decimalnotation).

A description will be given below with respect to how to producespecific data in accordance with the above data conversion rule. First,data symbol “164” (=“0A4h”) is set to main data “D0 to D2047” in thedata frame structure described previously. Next, a data frame 1 to adata frame 15 are pre-scrambled in advance by an initial preset number“0Eh”, and a data frame 16 to a data frame 31 are pre-scrambled inadvance by an initial preset number “0Fh”. If pre-scrambling is appliedin advance, when scrambling is applied in the data conversion ruledescribed previously, scrambling is applied in duplicate, and a datasymbol “164” (=“0A4h”) appears as it is (when scrambling is applied induplicate, an original pattern is returned). When pre-scrambling isapplied to all of the reference codes, each of which is formed of 32physical sectors, DSV control cannot be made, and thus, pre-scramblingcannot be applied to only data frame 0 in advance. After the foregoingscrambling has been applied, if modulation is carried out, a patternshown in FIGS. 24A, 24B, 24C, and 24D is recorded on the informationstorage medium.

In the invention, address information in a recording type(rewritable-type or write-once) information storage medium is recordedin advance by using wobble modulation. The present embodiment isfeatured in that phase modulation of ±90 degrees (180 degrees) is usedas a wobble modulation system, and NRZ (Non Return to Zero) method isemployed, recording address information in advance with respect to aninformation storage medium. A specific description will be given withreference to FIG. 21. In the present embodiment, with respect to addressinformation, the 1-address bit (referred to as an address symbol) area511 is expressed by a four-wobble cycle, and a frequency and anamplitude/a phase are matched everywhere in the 1-address bit area 511.In the case where the same values of address bits are continued, thesame phase continuously lasts at the boundary section of the 1-addressbit areas 511 (at a portion indicated by “triangular mark” shown in FIG.21). In the case where an address bit is inverted, wobble patterninversion (180-degree shift of phase) occurs.

In the wobble signal detector unit 135 of the informationrecording/reproducing apparatus shown in FIG. 8, a boundary position ofthe above address bit area 511 (location indicated by “triangular mark”shown in FIG. 21) and a slot position 412 which is a boundary positionof a 1-wobble cycle are detected at the same time. Although not shown inthe wobble signal detector unit 135, a PLL (Phase Lock Loop) circuit isincorporated, and PLL is applied in synchronism with both of theboundary position of the above address bit area 511 and the slotposition 412. If the boundary position of this address bit area 511 orthe slot position 412 is shifted, the wobble signal detector unit 135 isout of synchronization, disabling precise wobble signal reproduction(reading). A gap between the adjacent slot positions 412 is referred toas a slot gap 513. As this slot gap 513 is physically closer,synchronization with a PLL circuit can be easily obtained, enablingstable wobble signal reproduction (reading of contained information).

As is evident from FIG. 21, this slot gap 513 coincides with a 1-wobblecycle if the phase modulation method of 180° is used in which the phaseis shifted by 0° or 180°. As a wobble modulating method, although an AM(Amplitude Modulation) system for changing a wobble amplitude is easilyaffected by dust or scratch adhering to the information storage mediumsurface, the above phase modulation is hardly comparatively affected bydust or scratch adhering to the information storage medium surfacebecause a change of a phase is detected instead of a signal amplitude inthe above phase modulation. As another modulation system, in an FSK(Frequency Shift Keying) system for changing a frequency, a slot gap 513is long with respect to a wobble cycle, and synchronization of a PLLcircuit is relatively hardly obtained. Therefore, as in the presentembodiment, when address information is recorded by wobble phasemodulation, there is attained advantageous effect that a slot gap isnarrow, and wobble signal synchronization is easily obtained.

As shown in FIG. 21, although binary data “1” or “0” is assigned to the1-address bit area 511, a method for allocating bits in the presentembodiment is shown in FIG. 22. As shown on the left side of FIG. 22, awobble pattern, which first wobbles from the start position of onewobble to the outer periphery side, is referred to as an NPW (NormalPhase Wobble), and data “0” is arranged. As shown at the right side, awobble pattern which first wobbles from the start position of one wobbleto the inner periphery side is referred to as an IPW (Invert PhaseWobble), and data “1” is arranged.

As shown in FIGS. 7B and 7C, the width Wg of the pre-groove region 11 islarger than the width Wl of the land region 12. Thus, a problem occursin which the detection signal level of the wobble detection signal islowered and the C/N ratio is lowered. Contrary to the prior art, anon-modulated area is wider than a modulated area so that the stabilityfor detecting a wobble signal is improved.

A description will be given with respect to a wobble address format inan H format of the embodiment with reference to FIGS. 30A to 106E. Asshown in FIG. 30B, a physical segment block includes seven physicalsegments 550-556. As shown in FIG. 30C, each of the physical segments550-556 includes seventeen wobble data units 560-576. Each of the wobbledata units 560-576 includes a modulation area which includes one of awobble sync area 580, modulation start marks 581, 582, wobble addressareas 586, 587 and non-modulation areas 590, 591 which includecontinuous NPWs. FIGS. 23A to 23D show a ratio of the non-modulationarea and the modulation area of each wobble data unit. In each of FIGS.23A to 23D, the modulation area 598 includes 16 wobbles and thenon-modulation area 593 includes 68 wobbles. According to theembodiment, the non-modulation area 593 is wider than the modulationarea 598. Since the non-modulation area 593 is wide, it is possible tostably synchronize the wobble detection signal, write clock, orreproduction clock by the PLL circuit using the signal from thenon-modulation area 593. In order to perform a stable synchronization,it is desirable set the width of the non-modulation area 593 at leastdouble of that of the modulation area 598.

A description will be given with respect to an address informationrecording format using wobble modulation in an H format of a write-oncetype information storage medium according to the invention. An addressinformation setting method using wobble modulation in the presentembodiment is featured in that “allocation is carried out in units ofthe sync frame length 433”. One sector is composed of 26 sync frames,and, one ECC block is formed of 32 physical sectors. Thus, one ECC blockis composed of 32 physical sectors and is composed of 832 (=26×327) syncframes.

Wobble data is divided into 17 WDU (Wobble Data Units), respectively, ona physical segment by segment basis. From the above formula, it isevident that seven sync frames are arranged to a length of one wobbledata unit, respectively. Thus, a physical segment is composed of 17wobble data units, and seven physical segment lengths are adjusted toconform to a data segment length, thereby making it easy to allocate async frame boundary and detect a sync code in a range encompassing guardareas 442 to 468.

Each of the wobble data units #0 560 to #11 571 is composed of: amodulation area 598 for 16 wobbles; and non-modulation areas 592 and 593for 68 wobbles, as shown in FIGS. 23A to 23D. The present embodiment isfeatured in that an occupying ratio of the non-modulation areas 592 and593 with respect to a modulation area is significantly large. In thenon-modulation areas 592 and 593, a group area or a land area alwayswobbles at a predetermined frequency, and thus, a PLL (Phase LockedLoop) is applied by utilizing the non-modulation areas 592 and 593,making it possible to stably sample (generate) a reference clock whenreproducing a recording mark recorded in the information storage mediumor a recording reference clock used at the time of new recording. Thus,in the present embodiment, an occupying ratio of the non-modulationareas 592 and 593 with respect to a modulation area 598 is significantlyincreased, thereby making it possible to remarkably improve theprecision of sampling (generating) a recording reference clock andremarkably improving the stability of the sampling (generation). Thatis, in the case where phase modulation in wobbles has been carried out,if a reproduction signal is passed through a band path filter for thepurpose of waveform shaping, there appears a phenomenon that a detectionsignal waveform amplitude after shaped is reduced before and after aphase change position. Therefore, there is a problem that, when thefrequency of a phase change point due to phase modulation increases, awaveform amplitude change increases, and the above clock samplingprecision drops; and, conversely, if the frequency of a phase changepoint in a modulation area is low, a bit shift at the time of wobbleaddress information detection is likely to occur. Thus, in the presentembodiment, there is attained advantageous effect that a modulation areaand a non-modulation area due to phase modulation configured, and anoccupying ratio of the non-modulation area is increased, therebyimproving the above clock sampling precision.

In the present embodiment, a position of switching the modulation areaand the non-modulation area can be predicted in advance. Thus, areproduction signal is gated to obtain a signal from the non-modulationarea, making it possible to carry out the above clock sampling from thatdetection signal. In addition, in the case where the recording layer 3-2is composed of an organic dye recording material using a principle ofrecording according to the present embodiment, a wobble signal iscomparatively hardly taken in the case of using the pre-grooveshape/dimensions described in “3-2-D] Basic characteristics relevant topre-groove shape/dimensions in the present embodiment” in “3-2)Description of basic characteristics common to organic dye film in thepresent embodiment”. In consideration of this situation, the reliabilityof wobble signal detection is improved by significantly increasing anoccupying ratio of the non-modulation areas 590 and 591 with respect toa modulation area, as described above.

At the boundary between the non-modulation areas 592 and 593 and themodulation area 598, an IPW area is set as a modulation start mark ofthe modulation area 598 by using four wobbles or six wobbles. At awobble data section shown in FIGS. 23C and 23D, allocation is carriedout so that wobble address areas (address bits #2 to #0)wobble-modulated immediately after detecting the IPW area which is thismodulation start mark. FIGS. 23A and 23B each show the contents in awobble data unit #0 560 which corresponds to a wobble sync area 580shown in FIG. 24C described later; and FIGS. 23C and 23D each show thecontents in a wobble data unit which corresponds to a wobble datasection from segment information 727 to a CRC code 726 shown in FIG.24C. FIGS. 23A and 71C each show a wobble data unit which corresponds toa primary position 701 in a modulation area described later; and FIGS.23B and 23D each show a wobble data unit which corresponds to asecondary position 702 in a modulation area. As shown in FIGS. 23A and23B, in a wobble sync area 580, six wobbles are allocated to the IPWarea, and four wobbles are allocated to an NPW area surrounded by theIPW area. As shown in FIGS. 23C and 23D, four wobbles are allocated to arespective one of the IPW area and all of the address bit areas #2 to #0in the wobble data section.

FIGS. 24A to 24D shows an embodiment relating to a data structure inwobble address information in a write-once type information storagemedium. For the sake of comparison, FIG. 24A shows a data structure inwobble address information of a rewritable-type information storagemedium. FIGS. 24A and 24C show two embodiments relating to a datastructure in wobble address information in the write-once typeinformation storage medium.

In a wobble address area 610, three address bits are set by 12 wobbles(referring to FIG. 21). Namely, one address bit is composed of fourcontinuous wobbles. Thus, the present embodiment employs a structure inwhich address information is arranged to be distributed on three bythree address bit basis. When the wobble address information 610 isintensively recorded at one site in an information storage medium, itbecomes difficult to detect all information when dust or scratch adheresto the medium surface. As in the present embodiment, there is attainedadvantageous effect that: wobble address information 610 is arranged tobe distributed on a three by three address bit (12 wobbles) basisincluded in one of the wobble data units 560 to 576; and a set ofinformation is recorded on an integer multiple by multiple address bitbasis of three address bits, enabling information detection of anotheritem of information even in the case where it is difficult to detectinformation in one site due to dust or scratch.

As described above, the wobble address information 610 is arranged to bedistributed, and the wobble address information 610 is completelyarranged on a one by one physical segment basis, thereby making itpossible to identify address information on a physical segment bysegment basis, and thus, identify a current position in physical segmentunits every time an information recording/reproducing apparatus providesan access.

In the present embodiment, an NRZ technique is employed as shown in FIG.21, and thus, a phase does not change in four continuous wobbles in thewobble address area 610. A wobble sync area 580 is set by utilizing thischaracteristic. That is, a wobble pattern which is hardly generated inthe wobble address information 610 is set with respect to the wobblesync area 580, thereby facilitating allocation position identificationof the wobble sync area 580. The present embodiment is featured in that,with respect to wobble address areas 586 and 587 in which one addressbit is composed of four continuous wobbles, one address bit length isset at a length other than four wobbles at a position of the wobble syncarea 580. That is, in the wobble sync area 580, as shown in FIGS. 23Aand 23B, an area (IPW area) in which a wobble bit is set to “1” is setas a wobble pattern change which does not occur in the wobble datasection as shown in FIGS. 23C and 23D such as “six wobbles→fourwobbles→six wobbles”. When a method for changing a wobble cycle asdescribed above is utilized as a specific method for setting a wobblepattern which can be hardly generated in the wobble data section withrespect to the wobble sync area 580, the following advantageous effectscan be attained:

1) Wobble detection (wobble signal judgment) can be stably continuedwithout distorting PLL relating to the slot position 512 (FIG. 21) of awobble which is carried out in the wobble signal detector unit 135 shownin FIG. 8; and

2) A wobble sync area 580 and modulation start marks 561 and 562 can beeasily detected due to a shift of an address bit boundary positiongenerated in the wobble signal detector unit 135 shown in FIG. 8.

As shown in FIGS. 23A to 23D, the present embodiment is featured in thatthe wobble sync area 580 is formed in 12 wobble cycles, and a length ofthe wobble sync area 580 is made coincident with three address bitlengths. In this manner, all the modulation areas (for 16 wobbles) inone wobble data unit #0 560 are arranged to the wobble sync area 580,thereby improving detection easiness of the start position of wobbleaddress information 610 (allocation position of wobble sync area 580).This wobble sync area 580 is arranged in the first wobble data unit in aphysical segment. Thus, there is attained advantageous effect that thewobble sync area 580 is arranged to the start position in a physicalsegment, whereby a boundary position of the physical segment can beeasily sampled merely by detecting a position of the wobble sync area580.

As shown in FIGS. 23C and 23D, in wobble data units #1 561 to #11 571,the IPW area (refer to FIG. 22) is arranged as a modulation start markat the start position, the area preceding address bits #2 to #0. Thewaveform of NPW is continuously formed in the non-modulation areas 592and 593 arranged at the preceding position. Thus, the wobble signaldetector unit 135 shown in FIG. 8 detects a turning point from NPW toIPW is detected, and samples the position of the modulation start mark.

As a reference, the contents of wobble address information 610 containedin a rewritable-type information storage medium shown in FIG. 24A are asfollows:

1) Physical Segment Address 601

Information indicating a physical segment number in a track (within onecycle in an information storage medium 221);

2) Zone Address 602

This address indicates a zone number in the information storage medium221; and

3) Parity Information 605

This information is set for error detection at the time of reproductionfrom the wobble address information 610; 14 address bits from reservedinformation 604 to the zone address 602 are individually added in unitsof address bits; and a display as to whether or not a result of theaddition is an even number or an odd number is made. A value of theparity information 605 is set so that a result obtained by takingexclusive OR in units of address bits becomes “1” with respect to atotal of 15 address bits including one address bit of this addressparity information 605.

4) Unity Area 608

As described previously, each wobble data unit is set so as to becomposed of a modulation area 598 for 16 wobbles and non-modulationareas 592 and 593 for 68 wobbles, and an occupying ratio of thenon-modulation areas 592 and 593 with respect to the modulation area 598is significantly increased. Further, the precision and stability ofsampling (generation) of a reproducing reference clock or a recordingreference clock is improved more remarkably by increasing the occupyingratio of the non-modulation areas 592 and 593. The NPW area is fullycontinuous in a unity area 608, and is obtained as a non-modulation areahaving its uniform phase.

FIG. 24A shows the number of address bits arranged to each item of theabove described information. As described above, the wobble addressinformation 610 is divided on a three by three address bits, and thedivided items of the information are arranged to be distributed in eachwobble data unit. Even if a burst error occurs due to the dust orscratch adhering to a surface of an information storage medium, there isa very low probability that such an error propagates across the wobbledata units which are different from each other. Therefore, a contrivanceis made so as to reduce to the minimum the count encompassing thedifferent wobble data units as locations in which the same informationis recorded and to match the turning point of each items of informationwith a boundary position of a wobble data unit. In this manner, even ifa burst error occurs due to the dust or scratch adhering to a surface ofan information storage medium, and then, specific information cannot beread, the reliability of reproducing of wobble address information isimproved by enabling reading of another item of information recorded inanother one of the wobble data units.

As shown in FIGS. 24A to 24D, the present embodiment is featured in thatthe unity areas 608 and 609 are arranged at the end in the wobbleaddress information 610. As described above, in the unity areas 608 and609, a wobble waveform is formed in the shape of NPW, and thus, the NPWcontinuously lasts in substantially three continuous wobble data units.There is attained advantageous effect that the wobble signal detectorunit 135 shown in FIG. 8 makes a search for a location in which NPWcontinuously lasts in a length for three wobble data units 576 byutilizing this feature, thereby making it possible to easily sample aposition of the unity area 608 arranged at the end of the wobble addressinformation 610, and to detect the start position of the wobble addressinformation 610 by utilizing the positional information.

From among a variety of address information shown in FIG. 24A, aphysical segment address 601 and a zone address 602 indicate the samevalues between the adjacent tracks, whereas a value changes between theadjacent tracks in a groove track address 606 and a land track address607. Therefore, an indefinite bit area 504 appears in an area in whichthe groove track address 606 and the land track address 607 arerecorded. In order to reduce a frequency of this indefinite bit, in thepresent embodiment, an address (number) is displayed by using a graycode with respect to the groove track address 606 and the land trackaddress 607. The gray code denotes a code in the case where a code afterconverted when an original value changes by “1” only changes by “onebit” anywhere. In this manner, the indefinite bit frequency is reduced,making it possible to detect and stabilize a reproduction signal from arecording mark as well as a wobble detecting signal.

As shown in FIGS. 24B and 24C, in a write-once type information storagemedium as well, as in the rewritable-type information storage medium, awobble sync area 580 is arranged at the start position of a physicalsegment, thereby making it easy to detect the start position of thephysical segment or a boundary position between the adjacent segments.Type identification information 721 on the physical segment shown inFIG. 24B indicates an allocation position in the physical segment as inthe wobble sync pattern contained in the above described wobble syncarea 580, thereby making it possible to predict in advance an allocationlocation of another modulation area 598 in the same physical segment andto prepare for next modulation area detection. Thus, there is attainedadvantageous effect that the precision of signal detection (judgment) ina modulation area can be improved. Specifically,

When type identification information 721 on a physical segment is set to“0”, it denotes that all the items of information in the physicalsegment shown in FIG. 26B are arranged at a primary position or that aprimary position and a secondary position shown in FIG. 26D are mixed;and

When type identification information 721 of a physical segment is set to“1”, all items of information in a physical segment are arranged at asecondary position, as shown in FIG. 26C.

According to another embodiment relevant to the above describedembodiment, it is possible to indicate an allocation location of amodulation area in a physical segment by using a combination between awobble sync pattern and type identification information 721 on aphysical segment. By using the combination of the two types ofinformation described previously, three or more types of allocationpatterns of modulation areas shown in FIGS. 26B to 26D can be expressed,making it possible to provide a plurality of allocation patterns of themodulation areas. While the above described embodiment shows anallocation location of a modulation area in a physical segment whichincludes a wobble sync area 580 and type identification information 721on a physical segment, the invention is not limited thereto. Forexample, as another embodiment, the wobble sync area 580 and the typeidentification information 721 on the physical segment may indicate anallocation location of a modulation area in a next physical segment. Bydoing this, in the case where tracking is carried out continuously alonga groove area, there is attained advantageous effect that the allocationlocation of the modulation area in the next physical segment can beidentified in advance, and a long preparation time for detecting amodulation area can be taken.

Layer number information 722 in a write-once type information storagemedium shown in FIG. 24B indicates either of the recording layers fromamong a single-sided single-layer or a single-sided double-layer. Thisinformation denotes:

“L0 later” in the case of a single-sided single-layer medium or asingle-sided double-layer medium when “0” is set (a front layer at thelaser light beam incident side); and

“L1 layer” of a single-sided double-layer when “1” is set (a rear layerin viewed from the laser light beam incident side).

Physical segment sequence information 724 indicates an allocationsequence of relative physical segments in the same physical segmentblock. As is evident as compared with FIG. 24A, the start position ofthe physical segment sequence information 724 contained in wobbleaddress information 610 coincides with that of a physical segmentaddress 601 contained in a rewritable-type information storage medium.The physical segment sequence information position is adjusted toconform with the rewritable-type medium, thereby making it possible toimprove compatibility between medium types and to share or simplify anaddress detection control program using a wobble signal in aninformation recording/reproducing apparatus in which both of arewritable-type information storage medium and a write-once typeinformation storage medium can be used.

A data segment address 725 shown in FIG. 24B describes addressinformation on a data segment in numbers. As has already been described,in the present embodiment, one ECC block is composed of 32 sectors.Therefore, the least significant five bits of a physical sector numberof a sector arranged at the beginning in a specific ECC block coincideswith that of a sector arranged at the start position in the adjacent ECCblock. In the case where a physical sector number has beet set so thatthe least significant five bits of the physical sector number of asector arranged in an ECC block are “00000”, the values of the leastsignificant six bits or more of the physical sector numbers of all thesectors which exist in the same ECC block coincide with each other.Therefore, the least significant five bit data of the physical sectornumber of the sectors which exist in the same ECC block is eliminated,and address information obtained by sampling only the least significantsix bits or more is defined as an ECC block address (or ECC blockaddress number). A data segment address 725 (or physical segment blocknumber information) recorded in advance by wobble modulation coincideswith the above ECC block address. Thus, when positional information on aphysical segment block due to wobble modulation is indicated by a datasegment address, there is advantageous effect that a data amountdecreases on five by five bit basis as compared with when the address isdisplayed by a physical sector number, simplifying current positiondetection at the time of an access.

A CRC code 726 shown in FIGS. 24B and 24C is a CRC code (errorcorrection code) arranged to 24 address bits from physical segment typeidentification information 721 to the data segment address 725 or a CRCcode arranged to 24 address bits from segment information 727 to thephysical segment sequence information 724. Even if a wobble modulationsignal is partially mistakenly read, this signal can be partiallycorrected by this CRC code 726.

In a write-once type information storage medium, an area correspondingto 15 address bits is arranged to the unity area 609, and an NPW area isfully arranged in five wobble data units 12 to 16 (the modulation area598 does not exist).

A physical segment block address 728 shown in FIG. 24C is an address setfor each physical segment block which configure one unit from sevenphysical segments, and a physical segment block address relevant to thefirst segment block in the data lead-in area DTRDI is set to “1358h”.The values of the physical segment block addresses are sequentiallyadded one by one from the first physical segment block contained in thedata lead-in area DTLDI to the last physical segment block contained inthe data lead-out area DTLDO, including the data area DTA.

The physical segment sequence information 724 denotes the sequence ofeach of the physical segments in one physical segment block, and “0” isset to the first physical segment, and “6” is set to the last physicalsegment.

The embodiment shown in FIG. 24C is featured in that the physicalsegment block address 728 is arranged at a position which precedes thephysical segment sequence information 724. For example, as in the RMDfield 1, address information is often managed by this physical segmentblock address. In the case where an access is provided to apredetermined segment block address in accordance with these items ofmanagement information, first, the wobble signal detector unit 135 shownin FIG. 8 detects a location of the wobble sync area 580 shown in FIG.24C, and then, sequentially decodes items of information recordedimmediately after the wobble sync area 580. In the case where a physicalsegment block address exists at a position which precedes the physicalsegment sequence information 724, first, the physical segment blockaddress is decoded, and it is possible to judge whether or not apredetermined physical segment block address exists without decoding thephysical segment sequence information 724. Thus, there is advantageouseffect that access capability using a wobble address is improved.

The segment information 727 is composed of type identificationinformation 721 and a reserved area 723. The type identificationinformation 721 denotes an allocation location of a modulation area in aphysical segment. In the case where the value of this typeidentification information 721 is set to “0b”, it denotes a state shownin FIG. 26B described layer. In the case where the information is set to“1b”, it denotes a state shown in FIG. 26C or FIG. 26D described later.

The present embodiment is featured in that type informationidentification 721 is arranged immediately after the wobble sync area580 in FIG. 24C. As described above, first, the wobble signal detectorunit 135 shown in FIG. 8 detects a location of the wobble sync area 580shown in FIG. 24C, and then, sequentially decodes the items ofinformation recorded immediately after the wobble sync area 580.Therefore, the type identification information 721 is arrangedimmediately after the wobble sync area 580, thereby enabling anallocation location check of a modulation area in a physical segmentimmediately. Thus, high speed access processing using a wobble addresscan be achieved.

In the present embodiment, an H format is used, and thus, thepredetermined value of the wobble signal is set to 697 kHz.

Now, a description will be given with respect to an example ofmeasurement of a maximum value (Cwmax) and a minimum value (Cwmin) of acarrier level of a wobble detection signal.

In the write-once type storage medium according to the presentembodiment, a CLV (Constant Linear Velocity) recording system is used,and thus, a wobble phase between the adjacent tracks changes dependingon a track position. In the case where the wobble phases between theadjacent tracks coincide with each other, the carrier level of thewobble detection signal is maximized, and is obtained as the maximumvalue (Cwmax). In addition, when the wobble phase between the adjacenttracks is inverted, the wobble detection signal level is minimized dueto the crosstalk of the adjacent tracks, and is obtained as the minimumvalue (Cwmin). Therefore, in the case where tracing is carried out alonga track from its inner periphery to its outer periphery, the size of acarrier of a wobble detection signal to be detected fluctuates in a4-track cycle.

In the present embodiment, a wobble carrier signal is detected on a 4×4track basis, and the maximum value (Cwmax) and the minimum value (Cwmin)are measured on a 4×4 track basis. Then, at #03, 30 pairs or more of themaximum value (Cwmax) and the minimum value (Cwmin) are stored.

Next, utilizing the formula below, at #04, the maximum amplitude(Wppmax) and the minimum amplitude (Wppmin) are calculated from anaverage value of the maximum value (Cwmax) and the minimum value(Cwmin).

In the formula below, R represents a terminated resistance value of thespectrum analyzer. Now, a description will be given with respect to aformula for converting Wppmax and Wppmin from the values of Cwmax andCwmin.

In a dBm unit system, 0 dBm=1 mW is defined as a reference. When powerWa=1 mW, a voltage amplitude Vo is obtained as follows:

Wao=Ivo=Vo×Vo/R= 1/1000 W.

Therefore, Vo=(R/1000)^(1/2) is obtained.

Next, a relationship between a wobble amplitude Wpp [V] and a carrierlevel Cw [dMb] monitored by the spectrum analyzer is as follows. Here,Wpp denotes a sine wave, and thus, when an amplitude is converted to anactually effective value, it follows:

Wpp−rms=Wpp/(2×2^(1/2))

Cw=20×log(Wpp−rms/Wo)[dBm]

Therefore, Cw=10×log(Wpp−rms/Vo)² is established.

When the log of the above formula is converted, it follows:

$\begin{matrix}{\left( {{Wpp} - {{rms}/{Vo}}} \right)^{2} = 10^{({{Cw}/10})}} \\{= \left\{ {\left\lbrack {{Wpp}/\left( {2 \times 2^{1/2}} \right)} \right\rbrack/{Vo}} \right\}^{2}} \\{= \left\{ {{{Wpp}/\left( {2 \times 2^{2}} \right)}/\left( {R/1000} \right)^{1/2}} \right\}^{2}} \\{= \left( {{{Wpp}^{2}/8}/\left( {R/1000} \right)} \right.}\end{matrix}$ $\begin{matrix}{{{WPP}\; 2^{2}} = {\left( {8 \times R} \right)/\left( {1000 \times 10^{({{Cw}/10})}} \right)}} \\{= {8 \times R \times 10^{({- 3})} \times 10^{({{Cw}/10})}}} \\{= {8 \times R \times 10^{{({{Cw}/10})}\mspace{14mu} {({- 3})}}}}\end{matrix}\begin{matrix}{{Wpp} = \left\{ {8 \times R \times 10\left( {{Cw}/10^{({- 3})}} \right\}^{1/2}} \right.} & (61)\end{matrix}$

As described above, the present embodiment attains the followingadvantageous effects:

1) A ratio of a minimum value (Wppmin) of an amplitude of a wobbledetection signal with respect to (I1-I2)pp that is a track shiftdetection signal is set to 0.1 or more, whereby a sufficiently largewobble detection signal is obtained as compared with a dynamic range ofthe track shift detection signal. As a result, the detection precisionof the wobble detection signal can be taken significantly.

2) A ratio between a maximum value (Wppmax) of an amplitude of a wobbledetection signal and a minimum value (Wppmin) of an amplitude of awobble detection signal is set to 2.3 or less, whereby a wobble signalcan be stably detected without being greatly affected by a crosstalk ofa wobble from the adjacent track.

3) A value of NBSNR of a result obtained by squaring a wobble detectionsignal is allocated to be equal to or greater than 26 dB, whereby astable wobble signal having a high C/N ratio can be allocated, and thedetection precision of the wobble signal can be improved.

In the write-once type information storage medium according to thepresent embodiment, a recording mark is formed on a groove area, and aCLV recording system is employed. In this case, as described previously,a wobble slot position is shifted between the adjacent tracks, and thus,interference between the adjacent wobbles is likely to occur with awobble reproduction signal. In order to eliminate this effect, in thepresent embodiment, a contrivance is made to shift a modulation area sothat modulation areas do not overlap each other between the adjacenttracks.

Specifically, as shown in FIG. 25, a primary position 701 and asecondary position 702 can be set as an allocation location of amodulation area. Basically, assuming that after only the primarypositions 701 are allocated, there occurs a location in which modulationareas partially overlap between the adjacent tracks, the part of theprimary positions 701 are changed to the secondary positions 702. Forexample, in FIG. 25, when a modulation area of a groove area 505 is setas the primary position, a modulation area of the adjacent groove area502 and a modulation area of a groove area 506 partially overlap on eachother. Thus, the modulation area of the groove area 505 is set to thesecondary position. In this manner, there is attained advantageouseffect that a wobble address can be stably reproduced by preventing theinterference between the modulation areas of the adjacent tracks in areproduction signal from a wobble address.

The specific primary position and secondary position relating to amodulation area is set by switching an allocation location in the samewobble data unit. In the present embodiment, an occupying ratio of anon-modulation area is set to be higher than that of a modulation areaso that, the primary position and the secondary position can be switchedmerely by making a mere allocation change in the same wobble data unit.Specifically, in the primary position 701, as shown in FIGS. 23A and23C, the modulation area 598 is arranged at the start position in onewobble data unit. In the secondary position 702, as shown in FIGS. 23Band 23D, the modulation area 598 is arranged at the latter half positionin one of the wobble data units 560 to 571.

A coverage of the primary position 701 and the secondary position 702shown in FIGS. 23A to 23D, i.e., a range in which the primary positionor the secondary position continuously lasts is defined in the range ofphysical segments in the present embodiment. That is, as shown in FIGS.26B to 26D, there are provided three types (plural types) of allocationpatterns of modulation areas in the same physical segment. When thewobble signal detector unit 135 shown in FIG. 8 identifies an allocationpattern of a modulation area in a physical segment based on theinformation contained in the type identification information 721 on aphysical segment, the allocation location of another modulation area 598in the same physical segment can be predicted in advance. As a result,there is attained advantageous effect that preparation for detecting anext modulation area can be made, thus making it possible to improve theprecision of signal detection (judgment).

FIG. 26B shows allocation of wobble data units in a physical segment,wherein the number described in each frame indicates wobble data unitnumbers in the same physical segment. A 0-th wobble data unit isreferred to as a sync field 711 as indicated at the first row. A wobblesync area exists in a modulation area in this sync field 711. First toeleventh wobble data units are referred to as an address field 712.Address information is recorded in a modulation area included in thisaddress field 712. Further, in twelfth to sixteenth wobble data units,all of the wobble patterns are formed in an NPW unity field 713.

A mark “P” described in FIGS. 26B, 26C and 26D indicates that amodulation area is set to a primary position in a wobble data unit; anda mark “S” indicates that a modulation area is set to a secondaryposition in a wobble data unit. A mark “U” indicates that a wobble dataunit is included in the unity field 713, and a modulation area does notexist. An allocation pattern of a modulation area shown in FIG. 26Bindicates that all the areas in a physical segment are set to theprimary position; and an allocation pattern of a modulation area shownin FIG. 26C indicates all areas in a physical segment are set to thesecondary position. In FIG. 26D, the primary position and the secondaryposition are mixed in the same physical segment; a modulation area isset to the primary position in each of 0-th to fifth wobble data units,and a modulation area is set to the secondary position in each of sixthto eleventh wobble data units. As shown in FIG. 26D, the primarypositions and the secondary positions are half divided with respect toan area obtained by adding the sync field 711 and the address field 712,thereby making it possible to finely prevent an overlap of modulationareas between the adjacent tracks.

Now, a description will be given with respect to a method for recordingthe data segment data described previously with respect to the physicalsegment or the physical segment block in which address information isrecorded in advance by wobble modulation as described above. Data isrecorded in recording cluster units serving as units of continuouslyrecording data in both of a rewritable-type information storage mediumand a write-once type information storage medium. Since a recordingcluster which is a rewriting unit is formed of one or more datasegments, it is possible to facilitate a mixing recording process withrespect to the same information storage medium. PC data (PC files) ofwhich a small amount of data is often rewritten many times and AV data(AV files) of which a large amount of data is continuously recorded onetime. That is, with respect to data used for a personal computer, acomparatively small amount of data is often rewritten many times.Therefore, a recording method suitable for PC data is obtained byminimally setting data units of rewriting or additional writing. In thepresent embodiment, an ECC block is composed of 32 physical sectors.This, a minimum unit for efficiently carrying out rewriting oradditional writing is obtained by carrying out rewriting or additionalwriting in data segment units including only one ECC block. Therefore, astructure in the present embodiment in which one or more data segmentsare included in a recording cluster which is a rewriting unit or anadditional writing unit is obtained as a recording structure suitablefor PC data (PC files). In AV (Audio Video) data, it is necessary tocontinuously record a very large amount of video image information andvoice information smoothly without any problem. In this case,continuously recorded data is collectively recorded as one recordingcluster. At the time of AV data recording, when a random shift amount, astructure in a data segment, or a data segment attribute and the like isswitched on a data segment by segment basis configuring one recordingcluster, a large amount of time is required for such a switchingprocess, making it difficult to carry out a continuous recordingprocess. In the present embodiment, it is possible to provide arecording format suitable for AV data recording for continuouslyrecording a large amount of data by configuring a recording clusterwhile data segments in the same format (without changing an attribute ora ransom shift amount and without inserting specific information betweendata segments) are continuously arranged. In addition, a simplifiedstructure in a recording cluster is achieved, and simplified recordingcontrol circuit and reproduction detector circuit are achieved, makingit possible to reduce the price of an information recording/reproducingapparatus or an information reproducing apparatus. A data structure inrecording cluster 540 in which data segments (excluding the extendedguard field 528) in the recording cluster are continuously arranged iscompletely identical to those of the read-only information storagemedium and the write-once type information storage medium. In this way,a common data structure is provided among all of the information storagemediums regardless of the read-only type, the write-once type, or therewritable-type, thus allocating medium compatibility. In addition, adetector circuit of the information recording/reproducing apparatus orthe information reproducing apparatus whose compatibility has beenarranged can be used in common; high reliability of reproduction can bearranged; and price reduction can be achieved.

In the guard zone of a rewritable medium, post amble areas 546 and 536;extra areas 544 and 534; buffer areas 547 and 537; VFO areas 532 and522; and pre-sync areas 533 and 523, and an extended guard field 528 isarranged only in the guard zone in location in which continuousrecording terminates. The present embodiment is featured in thatrewriting or additional writing is carried out so that the extendedguard area 528 and the succeeding VFO area 522 partially overlap eachother at a duplicate site 591 at the time of rewriting. By rewriting oradditional writing while partial duplication is maintained, it ispossible to prevent a gap (area in which no recording mark is formed)from being produced between the recording clusters. In addition, astable reproduction signal can be detected by eliminating inter-layercross talk in an information storage medium capable of carrying outrecording in a single-sided double recording layer.

The data size which can be rewritten in one data segment in the presentembodiment is 67+4+77376+2+4+16=77469 (data bytes). One wobble data unit560 is 6+4+6+68=84 (wobbles). One physical segment 550 is composed of 17wobble data units, and a length of seven physical segments 550 to 556coincides with that of one data segment 531. Thus, 84×17×7=9996(wobbles) are arranged in the length of one data segment 531. Therefore,from the above formula, 77496/9996=7.75 (data bytes/wobble) correspondsto one wobble.

An overlap portion of the succeeding VFO area 522 and the extended guardfield 528 follows 24 wobbles from the start position of a physicalsegment, and the starting 16 wobbles of a physical segment 550 arearranged in a wobble sync area 580, and the subsequent 68 wobbles arearranged in a non-modulation area 590. Therefore, an overlap portion ofthe VFO area 522 which follows 24 wobbles and the extended guard field528 is included in the non-modulation area 590. In this way, the startposition of a data segment follows the 24 wobbles from the startposition of a physical segment, whereby the overlap portion is includedin the non-modulation area 590. In addition, a detection time and apreparation time for recording process of the wobble sync area 580 canbe sufficiently taken, and thus, a stable and precise recording processcan be guaranteed.

A phase change recording film is used as a recording film of therewritable-type information storage medium in the present embodiment. Inthe phase change recording film, degradation of the recording filmstarts in the vicinity of the rewriting start/end position. Thus, ifrecording start/recording end at the same position is repeated, thereoccurs a restriction on the number of rewritings due to the degradationof the recording film. In the present embodiment, in order to alleviatethe above described problem, at the time of rewriting, J_(M+1)/12 databytes are shifted, and the recording start position is shifted atrandom.

Although the start position of the extended guard field 528 coincideswith that of the VFO area 522 in order to explain a basic concept,strictly, the start position of the VFO area 522 is shifted at random inthe present embodiment.

A phase change recording film is used as a recording film in a DVD-RAMdisc which is a current rewritable-type information storage medium aswell, the start/end positions of recording is shifted at random for thepurpose of improving the rewriting count. The maximum shift amount rangewhen random shifting has been carried out in the current DVD-RAM disc isset to 8 data bytes. A channel bit length (as data after modulated, tobe recorded in a disc) in the current DVD-RAM disc is set to 0.143 μm onaverage. In the rewritable-type information storage medium according tothe present embodiment, an average length of channel bits is obtained as(0.087+0.093)/2=0.090 (μm). In the case where a length of a physicalshift range is adjusted to conform with the current DVD-RAM disc, byusing the above value, the required minimal length serving as a randomshift range in the present embodiment is obtained as:

8 bytes×(0.143 μm/0.090 μm)=12.7 bytes

In the present embodiment, in order to allocate easiness of areproduction signal detecting process, the unit of random shift amounthas been adjusted to conform to “channel bits” after modulated. In thepresent embodiment, ETM modulation (Eight to Twelve modulation) forconverting 8 bits to 12 bits is used, and thus, formula expression whichindicates a random shift amount is designated by J_(m)/12 (data bytes)while a data byte is defined as a reference. Using the value of theabove formula, a value which can be taken by J_(m) is 12.7×12=152.4, andthus, J_(m) ranges 0 to 152. For the above described reason, in therange meeting the above formula, a length of the random shift rangecoincides with the current DVD-RAM disc, and the rewriting count similarto the current DVD-RAM disc can be guaranteed. In the presentembodiment, a margin is slightly provided with respect to the requiredminimal length in order to allocate the current or more rewriting count,and the length of the random shift range has been set to 14 (databytes). From these formulas, 14×12=168 is established, and thus, a valuewhich can be taken by J_(m) has been set in the range of 0 to 167. Asdescribed above, the random shift amount is defined in a range which iswider than J_(m)/12 (0≦J_(m)≦154), whereby a length of a physical rangerelevant to the random shift amount coincides with that of the currentDVD-RAM. Thus, there is attained advantageous effect that the repetitionrecording count similar to that of the current DVD-RAM can beguaranteed.

The lengths of the buffer area 547 and the VFO area 532 in the recordingcluster 540 become constant. The random shift amount J_(m) of all thedata segments 529 is obtained as the same value everywhere in the samerecording cluster 540. In the case of continuously recording onerecording cluster 540 which includes a large amount of data segments, arecording position is monitored from a wobble. That is, a position ofthe wobble sync area 580 shown in FIGS. 24A to 24D is detected, and, inthe non-modulation areas 592 and 593 shown in FIGS. 23C and 23D, thecheck of the recording position on the information storage medium ismade at the same time as recording while the number of wobbles iscounted. At this time, a wobble slip (recording at a position shifted byone wobble cycle) occurs due to mistaken wobble count or rotationnon-uniformity of a rotary motor which rotates the information storagemedium, and the recording position on the information storage medium israrely shifted. The information storage medium according to the presentembodiment is featured in that, in the case where a recording positionshift generated as described above has been detected, adjustment is madein the rewritable-type guard area 461, and recording timing correctionis carried out in the guard area 461. Now, an H format will be describedhere. This basic concept is employed in a B format, described later.Although important information for which bit missing or bit duplicationcannot be allowed is recorded in a postamble area 546, an extra area544, and a pre-sync area 533, a specific pattern is repeated in thebuffer area 547 and the VFO area 532. Thus, as long as this repetitionboundary position is arranged, missing or duplication of only onepattern is allowed. Therefore, in the present embodiment, in particular,adjustment is made in the buffer area 547 or the VFO area 532, andrecording timing correction is carried out.

In the present embodiment, an actual start point position defined as areference of position setting is set so as to match a position of wobbleamplitude “0” (wobble center). However, the position detecting precisionof a wobble is low, and thus, in the present embodiment, the actualstart point position allows a shift amount up to a maximum of ±1 databyte”, as “±1 max” is described.

The random shift amount in the data segment 530 is defined as J_(m) (asdescribed above, the random shift amounts of all the data segments 529coincide with each other in the recording cluster 540); and the randomshift amount of the data segment 531 to be additionally written isdefined as J_(m+1). As a value which can be taken by J_(m) and J_(m+1)shown in the above formula, for example, when an intermediate value istaken, J_(m)=J_(m+1)=84 is obtained. In the case where the positionalprecision of an actual start point is sufficiently high, the startposition of the extended guard field 528 coincides with that of the VFOarea 522.

In contrast, after the data segment 530 is recorded at the maximum backposition, in the case where the data segment 531 to be additionallywritten or rewritten has then been recorded in the maximum frontposition, the start position of the VFO area 522 may enter a maximum 15data bytes in the buffer area 537. Specific important information isrecorded in the extra area 534 that immediately precedes the buffer area537. Therefore, in the present embodiment, a length of the buffer area537 requires 16 data bytes or more. In the embodiment, a data size ofthe buffer area 537 is set to 15 data bytes in consideration of a marginof one data byte.

As a result of a random shift, if a gap occurs between the extendedguard area 528 and the VFO area 522, in the case where a single-sideddouble recording layer structure has been employed, there occurs aninter-layer crosstalk at the time of reproduction due to that gap. Thus,even if a random shift is carried out, a contrivance is made such thatthe extended guard field 528 and the VFO area 522 partially overlap eachother, and a gap is not produced. Therefore, in the present embodiment,it is necessary to set the length of the extended guard field 528 to beequal to or greater than 15 data bytes. The succeeding VFO area 522sufficiently takes 71 data bytes. Thus, even if an overlap area of theextended guard field 528 and the VFO area 522 slightly widens, there isno obstacle at the time of signal reproduction (because a time forobtaining synchronization of reproduction reference clocks issufficiently arranged in the VFO area 522 which does not overlap).Therefore, it is possible to set the value of the extended guard field528 to be greater than 15 data bytes. As has already been described, awobble slip rarely occurs at the time of continuous recording, and arecording position may be shifted by one wobble cycle. One wobble cyclecorresponds to 7.75 (≅8) data bytes, and thus, in the presentembodiment, a length of the extended guard field 528 is set to equal toor greater than 23 (=15+8) data bytes. In the embodiment, like thebuffer area 537, the length of the extended guard field 528 is set to 24data bytes in consideration of a margin of one data byte similarly.

It is necessary to precisely set the recording start position of therecording cluster 541. The information recording/reproducing apparatusaccording to the present embodiment detects this recording startposition by using a wobble signal recorded in advance in therewritable-type or write-once type information storage medium. As shownin FIGS. 23A to 23D, in all areas other than the wobble sync area 580, apattern changes from NPW to IPW in units of four wobbles. In comparison,in the wobble sync area 580, wobble switching units are partiallyshifted from four wobbles, and thus, the wobble sync area 580 can detecta position most easily. Thus, the information recording/reproducingapparatus according to the present embodiment detects a position of thewobble sync area 580, and then, carries out preparation for a recordingprocess, and starts recording. Thus, it is necessary to arrange a startposition of a recording cluster 541 in a non-modulation area 590immediately after the wobble sync area 580. The wobble sync area 580 isarranged immediately after switching position of a physical segment. Thelength of the wobble sync area 580 is defined by 16 wobble cycles.Further, after detecting the wobble sync area 580, eight wobble cyclesare required for preparation for the recording process in considerationof a margin. Therefore, even in consideration of a ransom shift, it isnecessary that the start position of the VFO area 522 which exists atthe start position of the recording cluster 541 is arranged rearward by24 wobbles or more from a switching position of a physical segment.

A recording process is carried out many times in a duplicate site 591 atthe time of rewriting. When rewriting is repeated, a physical shape of awobble groove or a wobble land changes (is degraded), and the wobblereproduction signal amount is lowered. In the present embodiment, acontrivance is made so that a duplicate site 591 at the rewriting or atthe time of additional writing is recorded in the non-modulation area590 instead of arriving in the wobble sync area 580 or wobble addressarea 586. In the non-modulation area 590, a predetermined wobble pattern(NPW) is merely repeated. Thus, even if a wobble reproduction signalamount is partially degraded, interpolation can be carried out byutilizing the preceding and succeeding wobble reproduction signals. Inthis way, the position of the duplicate site 591 at the rewriting or atthe time of additional writing has been set so as to be included in thenon-modulation area 590. Thus, there occurs advantageous effect that astable wobble detection signal from the wobble address information 610can be guaranteed while preventing degradation of the wobblereproduction signal amount due to the shape degradation in the wobblesync area 580 or wobble address area 586.

The above description mainly relates to a single-sided single-layerdisc. The following description relates to a single-sided multi-layer(herein, dual layer) disc. The same portions as those of the abovedescription will be indicated in the same reference numerals and theirdetailed description will be omitted.

Measurement Condition

The characteristics of a recording medium are determined in accordancewith DVD specifications, and it is necessary to test whether thespecifications are satisfied or not before selling the recording medium.For that purpose, a device for measuring characteristics of a recordingmedium is required, and measurement conditions of a measuring device aredetermined in the specifications. Characteristics of an optical head formeasuring characteristics of a medium are regulated as follows.

Wavelength λ: 405±5 nm

Polarization: circularly polarized light

Polarizing Beam Splitter PBS: Shall be used.

Numerical aperture: 0.65±0.01

Light intensity at the rim of the pupil of the objective lens: 55% to70% of the maximum intensity level

Wave front aberration after passing through an ideal substrate:0.033λmax

A Normalized detector size on a disc: 100<A/m2<144 μm, in which

A: the central detector area of the optical head

M: the transversal magnification from disc to detector

Relative intensity noise (RIN)* of laser diode: −125 dB/Hz (max).

*: RIN (dB/Hz)=10 log [(AC power density/Hz)/DC power

Cross-Sectional Structure of Single-Sided Dual Layer Recordable Disc

FIG. 31 shows a cross-sectional view of a single-sided dual layerrecordable disc (write-once disc). The single-sided dual layer disc hasthe first transparent substrate 2-3 made of polycarbonate at the side ofan incident plane (read surface) of a laser beam 9 emitted from anobjective lens. The first transparent substrate 2-3 has transparency fora wavelength of a laser beam. A wavelength of the laser beam is 405 (±5)nm.

A first recording layer (Layer 0) 3-3 is provided on a plane opposite tothe light incident plane of the first transparent substrate 2-3. Pitscorresponding to recording information are provided to the firstrecording layer 3-3. An optical semi-transparent layer 4-3 is providedon the first recording layer 3-3.

A space layer 7 is provided on the optical semi-transparent layer 4-3.The space layer 7 serves as a transparent substrate with respect toLayer 1, and has transparency for a wavelength of a laser beam.

A second recording layer (Layer 1) 3-4 is provided on a plane oppositeto the optical incident plane of the space layer 7. Pits correspondingto recording information are provided to the second recording layer 3-4.An optical reflection layer 4-4 is provided on the second recordinglayer 3-4. A substrate 8 is provided on the optical reflection layer4-4.

Thickness of Space Layer 7

A thickness of the space layer 7 in the single-sided dual layerwrite-once disc is 25.0±5.0 μm. If it is thinner, interlayer crosstalkis made greater, which makes it difficult to manufacture, and therefore,a measure of thickness is regulated. In a single-sided dual layerread-only recording medium, a thickness of the space layer 7 is 20.0±5.0μm. Because a write-once recording medium is under the influence ofinterlayer crosstalk greater than the case of a read-only recordingmedium, the single-sided dual layer write-once disc is made thicker toslight extent as compared with the read-only recording medium, and acenter value of the thickness of the space layer 7 is regulated to be 25μm or more.

Reflectivity Including Birefringence

Reflectivity in the system lead-in area and system lead-out area is 4.5to 9.0% for High-to-Low disc and 4.2 to 8.4% for Low-to-Highdisc.Reflectivity in the data lead-in area, data area, middle area, anddata lead-out area is 4.5 to 9.0% for Low-to-High disc.

The higher the reflectivity, the better. However, there are limitsthereto, and those are determined such that the number of times ofrepeat reproduction and characteristics of a reproduction signal satisfypredetermined standards. Because the recording layer serving as Layer 0must be semi-transparent, a refractivity thereof is lower than that of asingle layer.

Interlayer Crosstalk

As described above, a single-sided multilayer recording medium has theproblem (interlayer crosstalk) that reflected lights from other layershave an effect on a reproduction signal. To described in detail, when arecorded status of a signal of the other layer (for example, Layer 0) tobe irradiated with the reproduction beam is changed during reproductionof one layer (for example, Layer 1), the problem that a signal of Layer1 during reproduction is offset by the crosstalk is brought about.Further, when a signal is recorded on Layer 1, an optimum recordingpower varies depending on whether Layer 0 has been recorded orunrecorded. These problems result from, for example, the fact that thetransmittance and the reflectivity of the recording medium with Layer 0vary in accordance with a recorded status or an unrecorded status, orthat a thickness of the space layer cannot be made much greater in orderto reduce an optical aberration. However, it is extremely difficult tophysically reduce such characteristics. Then, an optical disc of thepresent embodiment has a feature that no offset in a signal is broughtabout by providing clearance (areas in constant recorded status) torespective layers.

Definition of the Clearance

In a dual layer disc, the bundle of light that is focused onto a layerof the disc spreads out on the other layer of the disc and reflects atthe other layer as well as the layer where the light focuses, as shownin FIG. 32. Thus, reading and writing of a layer are affected by theinfluence of the beam that is reflected at the other layer of the disc.To mitigate this influence, the status of the other layer of the discshould be uniform in terms of existence of recorded marks. The area thataffects the quality of reading and writing of a layer is defined on theother layer of the disc taking the focused point as a reference. Then,reading and writing at a point on a layer should be qualified by keepingthe area on the other layer of the disc uniform. The radial distance ofthe area is called “Clearance”. Refer to FIG. 33.

The Clearance is calculated considering three elements, the maximumrelative deviation of the radius between Layer 0 and Layer 1, themaximum relative radial run-out between Layer 0 and Layer 1 and theradius of the ray bundle on the other layer. These values are defined asfollows;

Maximum relative deviation of the radius between Layer 0 and Layer 1:

Rd _(max)=40 μm

Maximum relative radial run-out between Layer 0 and Layer 1:

Rr _(max)=(40+60)/2=50 μm

The theoretical radius of the ray bundle on the other layer:

R _(c) _(—) _(theoretical) =T _(sl)×tan(sin⁻¹(NA/n))=14 μm

where T_(sl) the maximum thickness of the space layer 30 μm, NA isnumerical aperture=0.65 and n is refractive index of the space layer1.5.

The practical radius, R_(c) _(—) _(principal) can be supposed to beabout 10 μm effectively, because the intensity of the ray bundle ishighest in the center and lowest in the rim.

The Clearance C1 of the disc is calculated by the following equation:

C1=Rd _(max) +Rr _(max) +R _(c) _(—) _(practical)=100 μm

The Information area format is constructed considering the clearance atthe edges of the areas in the Information area.

Note: FIG. 33 illustrates a concept of the position shifts.

The relative deviation of the radius doesn't necessarily cause anoutward shift in Layer 1, and the relative radial run-out doesn'tnecessarily cause a inward shift in Layer 0.

Example of the Clearance in the Number of Physical Sectors

It is useful to simplify the Clearance in the number of Physical sectorsfrom a viewpoint of compatibility. A_(M) in FIG. 35 should be used forthe clearance in the number of Physical sectors at the location of M(Refer to FIG. 34).

FIG. 34 shows a physical sector number PSN of Layer 0 and a recordablephysical sector of Layer 1 corresponding to the physical sector numberPSN. The physical sector numbers of Layer 0 and Layer 1 have a bitinverted relation.

General Parameters

General parameters of single-sided dual layer write-once disc is shownin FIG. 36. These parameters are similar to the general parameters ofsingle-sided single layer write-once disc. Followings are different fromthose of those of single-sided single layer write-once disc; user datacapacity (30 GB), data area inner radius (24.6 mm for Layer 0, 24.7 mmfor Layer 1), and data area outer radius (58.1 mm for Layers 0 and 1).

Information Area Format

The information area is divided into 7 parts: the System Lead-in area,Connection area, Data Lead-in area, Data area, Middle area, DataLead-out area, and System Lead-out area. There is only one informationarea extending over two layers. The Middle area on each layer allows theread-out beam to move from Layer 0 to Layer 1. Refer to FIG. 40. TheData area is intended for recording of the main data. The System Lead-inarea contains the Control data and Reference code. The Data Lead-outarea allows for a continuous smooth read-out.

Track Structure

The System Lead-in area and System Lead-out area contain tracks whichconsist of a series of embossed pits. A track in System Lead-in area andSystem Lead-out area forms a 360° turn of a continuous spiral. Thecenter of the track is the center of the pits.

A track from Data Lead-in area to Middle area on Layer 0 and that fromMiddle area to Data Lead-out area on Layer 1 form a 360° turn of acontinuous spiral.

The Data Lead-in area, Data area and Middle area on Layer 0, and theMiddle area, Data area and Data Lead-out area on Layer 1 consist of aseries of groove tracks. The groove tracks are continuous from the startof the Data Lead-in area to the end of the Middle area on Layer 0 andthe start of the Middle area to the end of the Data Lead-out area onLayer 1. If two single-sided single layer discs are pasted on eachother, a double-sided dual layer disc having two read-out surfaces ismanufactured.

Layer is to be defined against the one read-out side of the disc. An HDDVD-R for dual layer disc has two layers identified as Layer 0 and Layer1 per read-out side. Layer 0 is the layer nearest to the read-outsurface and Layer 1 is the layer farthest to the read-out surface.

HD DVD-R for dual layer discs can be single-sided or double-sided. Fordouble-sided discs there are four layers. Two layers of each side areaccessed individually through the opposite sides of the disc.

Direction of Rotation

The disc rotates counterclockwise as viewed from the read-out side. Thetrack spirals outward from the inner diameter to the outer diameter onLayer 0. The track spirals inward from the outer diameter to the innerdiameter on Layer 1.

Track Layout

Each track in the System Lead-in area and System Lead-out area isdivided into Data segments. Each track in the data Lead-in area, dataarea, data Lead-out area, and middle area is divided into PS (PhysicalSegment) blocks. Each PS block should be divided into seven physicalsegments. Each Physical segment comprises 11067 bytes.

Lead-In Area, Lead-Out Area and Middle Area

The schematic of the Lead-in area and the Lead-out area is shown in FIG.37. The schematic of the original Middle area on Layer 0 and Layer 1 isshown in FIG. 38. The layout of the Middle area can be changed by Middlearea expansion. FIG. 38 shows an original Middle area before expansion.The border of each zone and each area in Lead-in area, Lead-out area andMiddle area coincides with the border of Data segments.

A system lead-in area, a connection area, a data lead-in area, and adata area are provided in sequence from the innermost periphery at theinner peripheral side of Layer 0. A system lead-out area, a connectionarea, a data lead-out area, and a data area are provided in sequencefrom the innermost periphery at the inner peripheral side of Layer 1. Inthis way, because the data lead-in area including a management area isprovided to only Layer 0, information on the layer L1 are also writteninto the data lead-in area of the Layer 0 at the time of finalizing onLayer 1. As a consequence, all the management information can beobtained by merely reading Layer 0 on start-up, and there is theadvantage that there is no need to read Layer 0 and Layer 1 one by one.Note that, in order to record data on Layer 1, the whole Layer 0 must bewritten. The management area is to be filled at the time of finalizingthe disc.

The system lead-in area of Layer 0 is composed of an initial zone, abuffer zone, a control data zone, and a buffer zone in sequence from theinner peripheral side. The data lead-in area of Layer 0 is composed of ablank zone, a guard track zone, a drive test zone, a disc test zone, ablank zone, an RMD duplication zone, an L-RMD (recording management zonein Data Lead-in area), an R-physical format information zone, and areference code zone in sequence from the inner peripheral side. Astarting address (inner peripheral side) of the data area of Layer 0 andan ending address (inner peripheral side) of the data area of Layer 1are shifted by a distance of a clearance, and the ending address (innerperipheral side) of the data area of Layer 1 is at a side outer than thestarting address (inner peripheral side) of the data area of Layer 0.

The data lead-out area of Layer 1 is composed of a blank zone, a disctest zone, a drive test zone, and a guard track zone in sequence fromthe inner peripheral side.

The blank zone is a zone having grooves, but having no data recordedthereon. The guard track zone is a zone on which a specific pattern fora test is recorded, and unmodulated data “00” is recorded thereon. Theguard track zone of Layer 0 is provided for recording onto the disc testzone and the drive test zone of Layer 1. Therefore, the guard track zoneof Layer 0 corresponds to a range obtained by adding at least clearanceto the disc test zone and the drive test zone of Layer 1. The guardtrack zone of Layer 1 is provided for recording onto the drive testzone, the disc test zone, the blank zone, the RMD duplication zone, theL-RMD, the R-physical format information zone, and the reference codezone of Layer 0. Therefore, the guard track zone of Layer 1 correspondsto a range obtained by adding at least clearance to the drive test zone,the disc test zone, the blank zone, the RMD duplication zone, the L-RMD,the R-physical format information zone, and the reference code zone ofLayer 0.

As shown in FIG. 38, both the middle areas of Layer 0 and Layer 1 eachare composed of the guard track zone, the drive test zone, the disc testzone, and the blank zone in sequence of the inner peripheral side. Theguard track zone of Layer 0 is provided for recording onto the drivetest zone and the disc test zone of Layer 1. Therefore, an endingposition of the guard track zone of Layer 0 is positioned at an outerperipheral side by at least a distance of a clearance from a startingposition of the disc test zone of Layer 1. The blank zone of Layer 1 isprovided for recording onto the drive test zone and the disc test zoneof Layer 0. Therefore, an ending position of the blank zone of Layer 1is positioned at an inner peripheral side by at least a distance of aclearance from a starting position of the drive test zone of Layer 0.

Track Path

In the present embodiment, an opposite track path as shown in FIG. 39 isused in order to maintain the continuity of recording from Layer 0 toLayer 1. In sequential recording, the routine does not proceed torecording onto Layer 1 unless recording onto Layer 0 is completed.

(Physical Sector Layout)

Each PS block contains 32 Physical sectors. On an HD DVD-R for duallayer disc, Physical sector numbers (PSN) of the Layer 0 continuouslyincreases in System Lead-in area and increases continuously from thebeginning of the Data Lead-in area to the end of the Middle area, asshown in FIG. 40. However, PSN of the Layer 1 takes the bit-invertedvalue to that of the Layer 0 and continuously increases from thebeginning of the Middle area (outside) to the end of the Data Lead-outarea (inside) and increases continuously from the outer side of theSystem Lead-out area to the inner side of the System Lead-out area.

The bit-inverted number is calculated so that the bit value of ONEbecomes that of ZERO and vice versa. Physical sectors on each layer withbit-inverted PSNs to each other are at almost the same distance from thecenter of the disc.

The Physical sector whose PSN is X is contained in the PS block whose PSblock address is calculated by dividing X by 32, rounding off fractions.

The PSNs in the System Lead-in area are calculated by letting thePhysical sector placed at the end of the System Lead-in area be “131071”(01 FFFFh).

The PSNs in the Layer 0 except for the System Lead-in area arecalculated by letting the PSN of the Physical sector placed at thebeginning of the Data area located after the Data Lead-in area be“262144” (04 0000h). The PSNs on the Layer 1 except for the SystemLead-out area are calculated by letting the PSN of the Physical sectorplaced at the beginning of the Data area located after the Middle areabe “9184256” (8C 2400h).

Physical Segment Structure

The Data Lead-in area, Data area, Middle area and Data Lead-out areacomprise Physical segments. A Physical segment is specified withPhysical segment order and PS block address.

WAP Layout

The Physical segment is aligned with Wobble Address in Periodic position(WAP) information modulated in the wobble. Each WAP information isindicated with 17 Wobble Data Unit (WDU). The length of Physical segmentis equal to the length of 17 WDU. The layout of WAP is shown in FIG. 41which corresponds to FIGS. 24C and 24D for the single-sided single layerdisc. The numbers in a field of a WAP layout indicate the WDU number inPhysical segment. The first WDU in the Physical segment is 0.

In the WAP, b0 to b8 describe CRC, and b9 to b11 describe physicalsegment orders, and b12 to b30 describe PS block addresses, and b31 tob32 describe segment information. Among the segment information, b31describes a reserved area, and b32 describes a type. A type denotes atype of a physical segment (0b is type 1 (FIG. 26B), and 1b is type 2(FIG. 26C) or type 3 (FIG. 26D). The PS block addresses are assigned tothe respective PS blocks. With respect to the physical segment orders,000b is set to the first physical segment in the PS block, and physicalsegment orders are assigned to the other six types of physical segmentsin the same way.

Wobble Data Unit

Wobble Data Unit (WDU) is consists of 84 wobbles. The period of wobblesis equal to 93T, where T denotes channel clock period. Primary WDU inSYNC field is shown in FIG. 42.

Primary WDU in Address field is shown in FIG. 43. 3 bits is recorded inthe Address field with 0b as Normal Phase Wobble (NPW) and 1b as InvertPhase Wobble (IPW).

Secondary WDU in SYNC field is shown in FIG. 44.

Secondary WDU in Address field is specified in FIG. 45. 3 bits isrecorded in the Address field with 0b as Normal Phase Wobble (NPW) and1b as Invert Phase Wobble (IPW).

WDU in Unity field is shown in FIG. 46. WDU for Unity field is notmodulated.

Modulation Rules of Bit

NPW and IPW are recorded on the track in the waveforms shown in FIG. 22.The start position of the physical segment coincides with the startposition of the SYNC field.

There are two possible modulated wobble positions, Primary WDU andSecondary WDU are shown in FIGS. 42 to 45. Normally the Primary WDU isselected. However, during the mastering process it is possible thatthere will already be a modulated wobble in the adjacent track. In sucha case, the Secondary WDU is selected to prevent from positioning themodulated wobble side by side, as shown in FIG. 25. Physical segmentsare categorized by the modulated wobble positions, called Type1, Type2and Type3, as shown in FIGS. 26A to 26D.

Type of Physical segment is selected according to the following rules.

1) Type1 or Type2 Physical segment is repeated equal to or more than 10times successively.

2) Type2 Physical segment is not repeated more than 28 timessuccessively.

3) Type3 Physical segment is selectable once at the transferringposition from Type1 Physical segment to Type2 Physical segment.

4) Modulated wobble positions is separated more than 2 wobble lengthfrom one of the adjacent track.

Lead-In Area, Lead-Out Area and Middle Area

The schematic of the Lead-in area and the Lead-out area is shown in FIG.47. The system lead-in area is composed of an initial zone, a bufferzone, a control data zone, and a buffer zone in sequence from the innerperipheral side. The connection area is composed of a connection zoneand a blank zone in sequence from the inner peripheral side. The datalead-in area is composed of a guard track zone, a drive test zone, adisc test zone, a blank zone, an RMD duplication zone, a recordingmanagement zone in the data lead-in area (L-RMD), an R-physical formatinformation zone, and the reference code zone in sequence from the innerperipheral side.

The details of the system lead-in area will be described. The initialzone contains embossed data segments. The main data of the data framerecorded as the data segment of the initial zone is set to “00h.”

The buffer zone consists of 1024 Physical sectors from 32 Data segments.The Main data of the Data frames eventually recorded as Data segments inthis zone is set to “00h.”

The Control data zone contains embossed Data segments. The Data segmentscontain embossed Control data. The Control data is comprised of 192 Datasegments starting from PSN 123904 (01 E400h). The structure of a Controldata zone is shown in FIG. 48.

The structure of a Data segment in a Control data section is shown inFIG. 49. The contents of the first Data segment in a Control datasection is repeated 16 times. The first Physical sector in each Datasegment contains the physical format information. The second Physicalsector in each Data segment contains the disc manufacturing information.The third Physical sector in each Data segment contains the copyrightprotection information. The contents of the other Physical sectors ineach Data segment are reserved for system use.

The structure of the physical format information included in the controldata section is shown in FIG. 50.

The explanation of the function of each Byte Position is describedbelow. The value specified for the Read power, Recording speeds,Reflectivity of Data area, Push-pull signal and On track signal given inBP 132-154 is only for example. Their actual values are decided by thedisc manufacture provided that the values are chosen within the valuessatisfying the emboss condition and the recorded user datacharacteristics.

The details of the data area allocation given in BP 4-15 are shown inFIG. 51. BP149 and BP152 specify reflectance ratios of the data areas ofLayer 0 and Layer 1. For example, 0000 1010b denotes 5%. An actualreflectance ratio is specified by the following formula.

Actual reflectance ratio=value×(½)

BP150 and BP153 specify push-pull signals of Layer 0 and Layer 1. Bit b7specifies a track shape of the disc of each layer. Bits b6 to b0 specifyamplitudes of the push-pull signals.

Track shape: 0b (track on a groove)

-   -   1b (track on a land)

Push-pull signal: for example, 010 1000b denotes 0.40.

An actual amplitude of a push-pull signal is specified by the followingformula.

Actual amplitude of push-pull signal=value×( 1/100)

BP151 and BP154 specify amplitudes of on-track signals of Layer 0 andLayer 1.

On-track signal: for example, 0100 0110b denotes 0.70.

An actual amplitude of an on-track signal is specified by the followingformula.

Actual amplitude of on-track signal=value×( 1/100)

Connection Area on Layer 0

The Connection area on Layer 0 is intended to connect the System Lead-inarea and the Data Lead-in area. The distance between the centerlines ofthe end Physical sector of the System Lead-in area, of which PSN is 01FFFFh, and the centerlines of the start Physical sector of the DataLead-in area, of which PSN is 02 6B00h, is 1.36 μm to 5.10 μm. If thedisc is a single layer disc, the upper limit of the distance is 10.20μm. This is because the interlayer crosstalk is present in the duallayer. It is preferable for the dual layer disc that the distance issmall. Connection area does not have any embossed pits or grooves.

Data Lead-In Area

The Data segments of the Blank zone do not contain data. The Datasegments of the Guard track zone are filled with 00h before recording onLayer 1. The Disc test zone is intended for quality tests by the discmanufacture. The Drive test zone is intended for tests by a drive. Thiszone is recorded from the outer PS block to the inner PS block. All theData segments of this zone are recorded before finalizing the disc.

RMD Duplication Zone

The RMD duplication zone consists of a RDZ Lead-in, as shown in FIG. 52.The RDZ Lead-in is recorded before recording the first RMD in the L-RMZ.The other fields of the RMD duplication zone are reserved and filledwith 00h. The size of the RDZ Lead-in is 64 kB and consists of theSystem Reserved Field (48 kB) and the Unique Identifier (ID) Field (16kB). The data in the System Reserved Field is set to 00h, and the UniqueID Field consists of eight units which have the same 2 kB size andcontents. The byte assignment of each unit includes the drivemanufacture ID, Serial number, Model number, and Unique Disc ID.

The Recording management zone in Data Lead-in area (L-RMZ) is recordedfrom PSN 03 CE00h to 03 FEFFh. The Recording management zone (RMZ)consists of Recording management data (RMD). The unrecorded part ofL-RMZ is recorded with the current RMD before finalizing the disc.

The Recording Management Data (RMD) contains the information about therecording on the disc. The size of the RMD is 64 kB. The data structureof RMD is shown in FIG. 53. Each RMD is formed of the main data of 2048bytes and recorded by a predetermined signal processing.

The RMD field 0 specifies general information of the disc, and thecontents of this field are shown in FIG. 54.

As a disc status of BP2,

00h: denotes that the disc is empty.

02h: denotes that the disc is recorded and not finalized.

03h: denotes that the disc is finalized.

08h: denotes that the disc is in a recording mode U.

11h: denotes that format operation is in progress. The others arereserved.

The details of the layout of data area allocation of BP22 to BP33 areshown in FIG. 55.

The details of the layout of renewed data area allocation of BP34 toBP45 are shown in FIG. 56.

The respective bits in a padding status of BP46 to 47 show thefollowings.

b15 . . . 0b: denotes that the inner guard track zone on Layer 0 is notpadded.

. . . 1b: denotes that the inner guard track zone on Layer 0 is padded.

b14 . . . 0b: denotes that the inner drive test zone on Layer 0 is notpadded.

. . . 1b: denotes that the inner drive test zone on Layer 0 is padded.

b13 . . . 0b: denotes that the RMD duplication zone is not padded.

. . . 1b: denotes that the RMD duplication zone is padded.

b12 . . . 0b: denotes that the reference code zone is not padded.

. . . 1b: denotes that the reference code zone is padded.

b11 . . . 0b: denotes that the outer guard track zone on Layer 0 is notpadded.

. . . 1b: denotes that the outer guard track zone on Layer 0 is padded.

b10 . . . 0b: denotes that the outer drive test zone on Layer 0 is notpadded.

. . . 1b: denotes that the outer drive test zone on Layer 0 is padded.

b9 . . . 0b: denotes that the extra guard track zone on Layer 0 is notpadded, or not assigned.

. . . 1b: denotes that the extra guard track zone on Layer 0 is padded.

b8 . . . 0b: denotes that the extra drive test zone on Layer 0 is notpadded, or not assigned.

. . . 1b: denotes that the extra drive test zone on Layer 0 is padded.b7 . . . 0b: denotes that the outer guard track zone on Layer 1 is notpadded.

. . . 1b: denotes that the outer guard track zone on Layer 1 is padded.

b6 to b5 . . . 00b: denotes that the recording of Terminator is notstarted.

. . . 01b: denotes that the recording of Terminator is in progress.

. . . 10b: denotes reserved.

. . . 11b: denotes that the recording of Terminator is finished.

The details of the layout of drive test zone of BP52 to BP99 are shownin FIG. 57. The RMD Field1 contains the OPC related information. In theRMD Field1 it is possible to record the OPC related information for upto 4 drives that may coexist in a system, as shown in FIGS. 58 and 59.

In the case of a single drive, the OPC related information is recordedin the field #1 and the other fields are set to 00h. In every case, theunused fields of the RMD Field1 are set to 00h. The OPC relatedinformation of the present drive is always recorded in the filed #1. Ifthe field #1 of the current RMD does not contain the present driveinformation, which consists of Drive manufacturer ID, Serial number andModel number, the information in the field #1 to #3 of the current RMDis copied to the field #2 to #4 of the new RMD and the information inthe field #4 of the current RMD is discarded. If the field #1 of thecurrent RMD contains the present drive information, the information inthe field #1 is updated and the information of the other fields iscopied to the field #2 to #4 of the new RMD.

Inner Drive test zone address for Layer 0 of BP72 to BP75, BP328 toBP331, BP584 to BP587, and BP840 to BP843:

These fields specify minimum PS block address of the drive test zone inthe data lead-in area onto which the most recent power calibration hasbeen carried out. When a current drive does not carry out powercalibration in the inner drive test zone of Layer 0, the inner drivetest zone address of Layer 0 of the current RMD is copied to the innerdrive test zone address of a new RMD. When these fields are set to“00h”, this test zone is not used.

Outer Drive test zone address for Layer 0 of BP76 to BP79, BP332 toBP335, BP588 to BP591, and BP844 to BP847:

These fields specify minimum PS block address of the drive test zone inthe middle area of Layer 0 onto which the most recent power calibrationhas been carried out. When a current drive does not carry out powercalibration in the outer drive test zone of Layer 0, the outer drivetest zone address of Layer 0 of the current RMD is copied to the outerdrive test zone address of a new RMD. When these fields are set to“00h”, this test zone is not used.

Test Zone Usage Descriptors of BP106, BP362, BP618, and BP874:

These fields specify descriptors for use of the four test zones. Therespective bits are assigned as follows.

b7 to b6 . . . Reserved areas.

b5 . . . 0b: The drive did not use the Extra drive test zone on Layer 0.

. . . 1b: The drive used the Extra drive test zone on Layer 0.

b4 . . . 0b: The drive did not use the Extra drive test zone on Layer 1.

. . . 1b: The drive used the Extra drive test zone on Layer 1.

b3 . . . 0b: The drive did not use the inner drive test zone on Layer 0.

. . . 1b: The drive used the inner drive test zone on Layer 0.

b2 . . . 0b: The drive did not use the outer drive test zone of Layer 0.

. . . 1b: The drive used the outer drive test zone on Layer 0.

b1 . . . 0b: The drive did not use the inner drive test zone on Layer 1.

. . . 1b: The drive used the inner drive test zone on Layer 1.

b0 . . . 0b: The drive did not use the outer drive test zone on Layer 1.

. . . 1b: The drive used the outer drive test zone on Layer 1.

Inner Drive test zone address of Layer 1 of BP108 to BP111, BP364 toBP367, BP620 to BP623, and BP876 to BP879:

These fields specify minimum PS block address of the drive test zone inthe data lead-out area onto which the most recent power calibration hasbeen carried out. When a current drive does not carry out powercalibration in the inner drive test zone of Layer 1, the inner drivetest zone address of Layer 1 of the current RMD is copied to the innerdrive test zone address of a new RMD. When these fields are set to“00h”, this test zone is not used.

Outer Drive Test Zone Address of Layer 1 of BP112 to BP115, BP368 toBP371, BP624 to BP627, and BP880 to BP883:

These fields specify minimum PS block address of the drive test zone inthe middle area of Layer 1 onto which the most recent power calibrationhas been carried out. When a current drive does not carry out powercalibration in the outer drive test zone of Layer 1, the outer drivetest zone address of Layer 1 of the current RMD is copied to the outerdrive test zone address of a new RMD. When these fields are set to“00h”, this test zone is not used.

The RMD field 2 specifies data for user's exclusive use. When this fieldis not used, “00h” is set into the field. BP0 to BP2047 are fields whichcan be used for data for user's exclusive use.

All the bytes of the RMD field 3 are reserved, and are set to “00h”.

The RMD field 4 specifies information of R zones. The contents of thisfield are shown in FIG. 60. A portion of the data area reserved in orderto record user data is called R zone. R zone can be classified into twotypes in accordance with a recording condition. In an Open R zone, datacan be added. In a Complete R zone, user data cannot be added. In a dataarea, three or more Open R zones cannot be provided. A portion of thedata area which is not reserved for recording data is called Invisible Rzone. An area following R zone can be reserved in the Invisible R zone.When data cannot be further added, there are no Invisible R zone.

The number of Invisible R zones of BP0 to BP1 is a total number of theInvisible R zones, the Open R zones, and the Complete R zones.

The RMD field 5 to the RMD field 21 specify information of R zones. Thecontents of these fields are shown in FIG. 61. When these fields are notused, all of those are set to “00h”.

The R physical format information zone in the data lead-in area isstructured from seven PS blocks (224 physical sectors) beginning at PSN261888 (03 FF00h). The contents of the first PS block in the R physicalformat information zone are repeated seven times. The configuration ofthe PS block in the R physical format information zone is shown in FIG.62.

The contents of the physical format information in the data lead-in areaare shown in FIG. 63. FIG. 63 is the same as FIG. 50 showing thecontents of the physical format information in the system lead-in area.BP0 to BP3 are copied from the physical format information in the systemlead-in area. The layout of the data area allocation of BP4 to BP15 isdifferent from that of FIG. 51, and is shown in FIG. 64. BP16 to BP2047are copied from the physical format information in the system lead-inarea.

(Middle Area)

The structure of the Middle area is changed by the Middle areaexpansion. The schematics of the Middle area before and after theexpansion are shown in FIGS. 65A to 65C. The structure of the Middlearea before the expansion is shown in FIG. 66. The size of the Guardtrack zone after the expansion and the creation of the Extra Guard trackzone on Layer 0 and the Extra Drive test zone depend on the end PSN ofthe Data area on Layer 0. The values Y and Z, which are the numbers ofPhysical sectors in the Guard track zone, are specified in FIG. 69.

Guard Track Zone

The Data segments of the Guard track zone on Layer 0 are filled with 00hbefore recording on Layer 1. The Data segments of the Guard track zoneon Layer 1 are filled with 00h before finalizing the disc.

Drive Test Zone

This zone is intended for tests by a drive. This zone on Layer 0 isrecorded from the outer PS block to the inner PS block. All the Datasegments of the Drive test zone on Layer 0 may be filled with 00h beforerecording on Layer 1.

Disc Test Zone

This zone is intended for tests by a disc manufacturer.

Blank Zone

The Data segments of the Blank zone do not contain data. The size of theoutermost Blank zone on Layer 0 is more than 968 PS blocks. The size ofthe outermost Blank zone on Layer 1 is more than 2464 PS blocks.

Structure of the Lead-Out Area

The structure of the Lead-out area is shown in FIG. 70.

The Data lead-out area is composed of a guard track zone, a drive testzone, a disk test zone, and a blank zone, in sequence from the outerperipheral side. The system lead-out area is composed of a systemlead-out zone.

Data segments of the guard track zone are filled with 00h beforefinalizing the disc.

The drive test zone is intended for tests by a drive. This zone isrecorded from the outer PS block to the inner PS block. Data segments ofthe blank zone do not contain data.

Connection Area on Layer 1

The Connection area on Layer 1 is intended to connect the Data Lead-outarea and the System Lead-out area. The distance between the centerlinesof the end Physical sector of the Data Lead-out area and the centerlinesof the start Physical sector of the System Lead-out area, of which PSNis FE 0000h, is 1.36 μm to 5.10 μm. Connection area does not have anyembossed pits or grooves.

All the main data of the data frame recorded as the physical sectors inthe System lead-out area are set to 00h.

Formatting

Formatting is a process applied when a disc is used and includesinitialization, data area allocation (middle area expansion), paddingand finalization.

Initialization

It is necessary to record information in the RDZ lead-in area in the RMDduplication zone and select a recording mode when the user data isrecorded in the disc.

Middle Area Expansion

Before recording in the Data area on Layer 1, the Middle area expansioncan be executed. The Middle area expansion enlarges the Middle area andshrinks the Data area at the same time. The structure of the Middle areais changed by Middle area expansion. The default end PSN of the Dataarea on Layer 0 is 73 DBFFh and the default start PSN of the Data areaon Layer 1 is 8C 2400h. Before recording in the Data area on Layer 1,the drive can reassign a PSN, which is less than 73 DBFFh, to the newend PSN of the Data area on Layer 0. The RMD Field0 is updated by theMiddle area expansion, and the new end PSN of the Data area on Layer 0is recorded in the R-Physical format information zone, except the Dataarea is relocated at finalization.

When the Middle area expansion is executed and the end PSN of the Dataarea on Layer 0 becomes X (<73 DBFFh), the bit-inverted number of X isthe start PSN of the Data area on Layer 1, an extra guard track zone onLayer 0 is formed, a blank zone on Layer 1 is formed, and a guard trackzone on Layer 1 is relocated, as shown in FIGS. 65A to 65C. When X<726C00h, an extra drive test zone and a blank zone are formed on Layer 0and an extra drive test zone on Layer 1 are formed.

Requirement Prior to Recording on Layer 1

Before recording on Layer 1 except for Terminator recording, some zonesshall be filled with 00h in order to prevent the influence of the Layer0.

In the case that the Middle area is not expanded, the Guard track zoneson Layer 0, which are located in the Data Lead-in area and Middle area,shall be filled with 00h. The Drive test zone in the Middle area onLayer 0 may be filled with 00h.

In the case that the Middle area is expanded with small size, the Guardtrack zones on Layer 0, which are located in the Data Lead-in area andMiddle area, and the Extra Guard track zone, which is located in theMiddle area on Layer 0, shall be filled with 00h, as shown in FIG. 65B.The Drive test zone in the Middle area on Layer 0 may be filled with00h.

In the case that the Middle area is expanded with large size, the Guardtrack zone which is located in the Data Lead-in area and the Extra Guardtrack zone, which is located in the Middle area on Layer 0, shall befilled with 00h, as shown in FIG. 65C. Before recording in the Drivetest zone on Layer 1, the Guard track zone which is located in theMiddle area on Layer 0 shall be filled with 00h. The Drive test zone andthe Extra Drive test zone in the Middle area on Layer 0 may be filledwith 00h.

When these zones are filled with ooh, then the information of the RMDField0 shall be updated.

Finalization

When the Data area is finalized, the Terminator is recorded in theunrecorded Data area, as shown in FIG. 77. Main data of the Terminatoris set to 00h, and the area type of it is the Data Lead-out attribute.In the case that user data are recorded on Layer 1, the Terminator isrecorded on all the unrecorded Data area.

In the case that user data are not recorded on Layer 1, the Terminatoris recorded on Layer 0 and Layer 1, as shown in FIGS. 77A and 77B. TheTerminator on Layer 0 is contiguously recorded from the end of the Dataarea. If there are amply unrecorded Data segments between the Data areaand the Middle area, then it is not necessary to record the Terminatoron all of them and it is permitted to create the Drive test zone onLayer 1, as shown in FIG. 78A. The size of the drive test zone is 480 PSblocks. The end PSN of the Terminator on Layer 0 and the start PSN ofthe Terminator on Layer 1 are specified in FIG. 72.

After recording the Terminator, the Guard track zones on Layer 1, whichare located in the Data Lead-out area and Middle area are filled with00h, if they are unrecorded. Before the Guard track zone which islocated in the Data Lead-out area is filled, the Drive test zone, theunrecorded part of the L-RMZ, the R-physical format information zone andthe Reference code zone which are located in the Data Lead-in area arerecorded.

If unrecorded data segment is present between the end PSN of theTerminator and the Middle area on Layer 0 as shown in FIG. 78A, it isunnecessary to record the Guard track zones which are located in theMiddle area on Layer 0 and Layer 1.

Conditions for measuring actuating signals of data lead-in area, dataarea, middle area, and data lead-out area

An offset canceler bandwidth is made to spread as compared with a singlelayer as follows.

−3 dB closed-loop bandwidth: 20.0 kHz

The bandwidth is 5 kHz in a single layer. However, the bandwidth is madeto spread in order to provide margin.

Burst Cutting Area Code (BCA-Code)

The BCA is an area for recording information after the completion of thedisc manufacturing process. It is permitted to write the BCA-Codethrough the replication process using pre-pits, if the read-out signalsatisfies the BCA-Code signal specification. The BCA exists on the Layer1 of a single-sided dual layer disc. Since the BCA exists on Layer 1 ofa single-sided dual layer read-only disc, the drive can be compatiblewith the recordable layer disc and the read-only disc.

Update Condition of RMD

RMD shall be update in at least one of the following conditions;

1) At least one of the contents specified in RMD Field0 is changed, or

2) Drive test zone address specified in RMD Field1 is changed, or

3) Invisible RZone number, First Open RZone number or Second RZonenumber specified in RMD Field4 is changed, or

4) The difference between the PSN of the least recorded Physical segmentin RZone #i and “Least recorded PSN of RZone #i” registered in the leastRMD becomes larger than 37888.

Updating RMD is not required in the above conditions 2) and 4) as longas the sequence of data recording operation is in process by an equal toor lee than 4 PS blocks.

Guideline to Select the Type of Physical Segment

As shown in FIG. 26, there are three types of allocation of a modulationarea in the physical segments of recordable information storage medium.The details of setting an allocation type of a modulation area atrespective diameters are described. The principle of the procedure isdescribed as follows.

The purpose of the type selection is to prevent from overlapping themodulated area in adjacent tracks. FIGS. 73A, 73B and 74 show a typeselection for tracks on Layer 0. For tracks on Layer 1, FIGS. 73A, 73Band 74 should be replaced with the figures for Layer 1 in the same wayas FIG. 71A is replaced with FIG. 71B for Layer 1. The principle of theprocedure is described as follows.

The purpose of the type selection is to prevent from positioning themodulated wobble side by side. A schematic of 2 adjacent tracks is shownin FIGS. 71A and 71B. The start point of the track #i is just the sameas that of Physical segment #n, where i and n denote natural numbers.The track #i consists of j Physical segments, k WDUs and m wobbles,where j denotes a natural number and k and m denote non-negativeintegers. If both k and m are not zero, then the Physical segment #n+jlocates in track #i and #i+1.

The relative position between the modulated wobbles in track #i and #i+1depends on m. If m is equal to or more than 21 and less than 63, thenType1 Physical segments should be selected in the track #i+1, as shownin FIG. 73A. Otherwise, Type2 Physical segments should be selected inthe track #i+1, as shown in FIG. 73B. For every case, Type1 Physicalsegments are selected in the track #i.

Type3 Physical segment is selectable once at the transferring positionfrom Type1 Physical segment to Type2 Physical segment. The selection ofType3 Physical segment depends on not only m but also k. An example ofthe case that Type3 Physical segment should be selected is shown in FIG.74. Type3 Physical segment should be selected in one of the followingconditions;

1) k is equal to or more than 6 and less than 12, and m is equal to ormore than 0 and less than 21, or

2) k is equal to or more than 5 and less than 11, and m is equal to ormore than 63 and less than 84.

A procedure for selecting a type of a physical segment is the same asthat of FIG. 75 according to the first embodiment. Repetitive processesin the procedure are executed for substantially two tracks. Therespective processes are shown hereinafter.

A length of the repetitive processes depends on the number of physicalsegments selected in the third step.

1) Estimation of the number of wobbles on one track (ST82)

Values of decimals of wobbles on a current track are estimated on thebasis of values on a previous track.

An integral value of wobble N_(W) can be obtained by rounding down thedecimals to an approximate value of an integer.

2) Calculation of j, k, and m (ST83)

j, k, and m are calculated as follows.

j=N _(W)−(N _(W) mod 1428)/1428,

m=N _(W) mod 84,

k=((N _(W) −m)/84) mod 17

Operation “x mod y” denotes a modulus after dividing x by y.

3) Selection of a type (ST84)

A type of a physical segment is selected in accordance with theconditions of k and m as follows.

21<m<63   Condition 1:

2j physical segments of type 1 are selected.

0<k<6 and 0<m<21, or 0<k and 63<m<84   Condition 2:

j physical segments of type 1 and j physical segments of type 2 areselected.

6<k<12 and 0<m<21, or 5<k<11 and 63<m<84   Condition 3:

j physical segments of type 1, one physical segment of type 3, and jphysical segments of type 2 are selected.

12<k<17 and 0<m<21, or 11<k<17 and 63<m<84   Condition 4:

j+1 physical segments of type 1 and j+1 physical segments of type 2 areselected.

A selection method for allocation type of a modulated area is shown inFIG. 75. When a selection procedure starts (ST 81), the number ofwobbles N_(W) for an inner track is estimated (ST 82). An integralnumber of wobbles N_(W) is can be gotten by rounding off the decimalfractional number to the nearest whole number. Calculation of j, k and mis performed (ST 83). The operation “x mod y” represents the modulusafter x divided by y. At ST 83, j, k and m are calculated as follows.

j={N _(W)−(N _(W) mod 1428)}/1428,   1)

m=N_(W) mod 84   2)

k={(N _(W) −m)/84} mod 17   3)

As shown in ST 84, the type (type1, type2, and type3) and the number ofiterations (j, 2j, j+1) are selected.

A type of a physical segment is selected in accordance with theconditions of k and m as follows.

21<m<63   Condition 1:

2j physical segments of type 1 are selected, as shown in FIG. 26B.

0≦k<6 and 0≦m<21, or 0≦k and 63≦m<84   Condition 2:

j physical segments of type 1 (FIG. 26B) and j physical segments of type2 (FIG. 26C) are selected.

6≦k<12 and 0≦m<21, or 5≦k<11 and 63≦m<84   Condition 3:

j physical segments of type 1 (FIG. 26B), one physical segment of type 3(FIG. 26B), and j physical segments of type 2 (FIG. 26C) are selected.

12≦k<17 and 0≦m<21, or 11≦k<17 and 63≦m<84   Condition 4:

j+1 physical segments of type 1 (FIG. 26B) and j+1 physical segments oftype 2 (FIG. 26C) are selected.

Procedures of ST 82 to ST 84 are performed for all tracks. When theprocedures of ST 82 to ST 84 for all tracks are performed (ST 85), theselection of the allocation type of the modulated area is ended (ST 86).

Light Fastness of the Disc

Light fastness of a disc is tested with an air-cooled Xenon lamp andtest apparatus complying with ISO-105-B02.

Test Conditions

Black Panel Temperature: <40° C.

Relative humidity: 70 to 80%

Disc Illumination:

Through the substrate, normal incident.

Write Power

The write power has four levels, Peak power, Bias power1, Bias power2and Bias power3. These are the optical powers incident on the read-outsurface of the disc and used for writing marks and spaces.

Peak power, Bias power1, Bias power2 and Bias power3 are given in theControl data zone. The maximum Peak power does not exceed 13.0 mW. Themaximum Bias power1, Bias power2 and Bias power3 do not exceed 6.5 mW.

Data Recording Procedure

FIG. 76 is a flow chart showing an operation performed when a non-usedinformation storage medium having a structure shown in FIGS. 37 and 38is inserted into a drive.

Insertion of a non-used blank disc starts an operation.

Data in a BCA area is read in step S2 to discriminate types of discs. Asthe types of the discs, there are single-sided/double-sided types,single layer/dual layer types, read-only/recordable/rewritable types,and the like. In this case, it is determined whether or not the inserteddisc is a single-sided dual layer disc.

An RDZ lead-in in an RMD duplication zone (RZD) of a data lead-in areais recorded in step S4, the RZD except for the RDZ lead-in is filled(padded) with “00h” in step S6. The RMD duplication zone includes theRDZ lead-in as shown in FIG. 52. The RDZ lead-in is recorded beforefirst recording management data RMD of a recording management zone L-RMZis recorded. Other fields of the RMD duplication zone are reserved andpadded with “00h”.

A recording management zone in the data lead-in area (L-RMZ) is recordedfrom “03 CE00h” to “03 FFFFh” of PSN. The recording management zone inthe data lead-in area L-RMZ includes recording position management dataRMD. An unrecorded area of the L-RMZ is recorded with current recordingposition management data RMD before the disc is finalized.

The recording position management data RMD in the data lead-in areaincludes information about a recording position of the disc. The size ofthe RMD is 64 kB, and a data configuration of the recording positionmanagement data RMD is shown in FIG. 53.

A data segment of a guard track zone of the data lead-in area is paddedin step S8.

Data is recorded in the data area of layer 0 in step S10. In this case,it is assumed that the size of the recorded data is equal to or largerthan the recording capacity of the data area of layer 0 and thatrecording in the data area of layer 0 and recording in the data area oflayer 1 are performed. Before the recording on layer 1, padding on layer0 is performed to finalize the disc. The finalizing is performed to makeit possible to read data by a player.

More specifically, a guard track zone of a middle area of layer 0 ispadded in step S12.

A drive test zone of a middle area of layer 0 is padded in step S14.Note that step S14 can be omitted.

A guard track zone of a middle area of layer 1 is padded in step S16.

Data is recorded in the data area of layer 1 in step S18.

Finalization after data recording on layer 1 is performed as follows.When the recording data is ended on the way of the data area of layer 1,a terminator is recorded on all unrecorded areas of the data area asshown in FIG. 77 in step S20. Main data of the terminator is set to“00h”, and the area type of the terminator is an attribute of a datalead-out area. When data is recorded in the entire data area of layer 1,the terminator is not recorded.

When no data area is recorded on layer 1, the terminator, as shown inFIGS. 78A and 78B, is recorded on both layer 0 and layer 1. Theterminator on layer 0 is recorded to be in contact with the data area.Sufficient unrecorded data segments are present between the data areaand a middle area, the terminator need not be recorded on all the datasegments. A new drive test zone is allowed to be formed on layer 1 (seeFIG. 78A). The size of the new drive test zone is 480 (PS block). An endPSN of the terminator of layer 0 and a start PSN of the terminator oflayer 1 are described above in Table 23.

The drive test zone of the data lead-in area of layer 0 is padded instep S22.

In step S24, a recording management zone in the data lead-in area(L-RMZ) of layer 0 is recorded.

An R physical format information zone RPFI of the data lead-in area oflayer 0 and a reference code zone Ref are recorded in step S26.

A guard track zone of a data lead-out area of layer 1 is padded in stepS28. The process subsequent to the recording of the terminator is thefinalizing process.

Thereafter, the disc is ejected.

Concrete orders of recording operations can be changed depending on thecontents of recording data, methods of controlling a drive, and thelike. A basic restriction about the recording orders are as follows.

When the guard track zone of the data lead-out area of layer 1 is padded(fill with “00h”) and if recording states of corresponding areas oflayer 0 are discontinuous (recorded area and unrecorded area coexist),stable recording cannot be performed because of the influence ofinterlayer crosstalk. All the corresponding areas of layer 0 must be ina recorded state. Therefore, before padding step S28 of the guard trackzone, step S4 (recording of RDZ lead-in of RZD (RMD duplication zone)),step S6 (padding of RMD duplication zone), step S8 (padding of datasegment of guard track zone of data lead-in area), step S22 (padding ofdrive test zone of data lead-in area), step S24 (recording of recordingmanagement zone in the data lead-in area (L-RMZ), and step S26(recording of R physical format information zone R-PFI of data lead-inarea and reference code zone Ref) must be performed. Furthermore, beforestep S24 (L-RMZ recording of data lead-in area), step S4 (recording ofRDZ lead-in) must be executed. However, the orders of steps S6, S8, S22,and S26 can be appropriately changed.

For the same reason as described above, step S12 of padding the guardtrack zone of the middle area of layer 0 and step S14 of padding thedrive test zone of the middle area of layer 0 must be performed beforestep S16 of padding the guard track zone of the middle area of layer 1.However, the orders of steps S12 and S14 can be appropriately changed.Before step S18 of recording data in the data area of layer 1, step S10of recording data in the data area of layer 0 and step S12 of paddingthe guard track zone of the middle area of layer 0 must be performed.However, the orders of steps S10 and S12 can be appropriately changed.

A modification of the recording operation in FIG. 76 will be describedbelow.

In shift from step S10 of recording data in the data area of layer 0 tostep S18 of recording data in the data area of layer 1, the middle areas(layer 0 and layer 1) are padded. In order to shorten the shift time,the padding may be performed at another timing. When a stream the datasize of which is not known in advance is to be recorded, data recordingis interrupted for a period of padding time. Therefore, in order toperform step S12 of padding the guard track zone of the middle area oflayer 0 at an earlier timing, step S12 may be executed before or afterany one of steps S4, S6, and S8. In order to perform step S16 of paddingthe guard track zone of the middle area of layer 1 at a later timing,step S16 may be executed before or after any one of steps S22, S24, andS26.

As another modification, in order to start data recording (step S10) inthe data area of layer 0 at a timing as early as possible, step S10 maybe executed immediately after step S4 (RDZ lead-in recording of RMDduplication zone), as shown in FIG. 79. In FIG. 79, the padding (stepS14) of the drive test zone of the middle area of layer 0 may beomitted. However, when the size of the recording data is larger than therecording capacity of the data area of layer 0, and the data may berecorded on both layer 0 and layer 1, some inconvenience occurs. In thiscase, as shown in FIG. 80, after step S12 (padding of guard track zoneof middle area of layer 0) is performed after step S4 (RDZ lead-inrecording of RMD duplication zone), step S10 (data recording in dataarea of layer 0) and step S18 (data recording inn data area of layer 1)may be executed. When the guard track zone of the middle area of layer 0is padded in step S12, recording on layer 1 can be started.

As a modification related to recording of a terminator, a case in whichthe terminator is recorded on only layer 0 and no terminator is recordedon layer 1 will be described below. When the terminator is not connectedto the middle area as shown in FIG. 78A, the terminator is recorded instep S20 after step S14 (padding of drive test zone of middle area oflayer 0) as shown in FIG. 81.

When the terminator is connected to the middle area as shown in FIG.78B, the terminator is recorded on layer 0 in step S20A after step S10(data recording step of layer 0), and the terminator is recorded onlayer 1 in step S20B after step S12 (padding of guard track zone ofmiddle area of layer 0) and step S14 (padding of drive test zone ofmiddle area of layer 0) as shown in FIG. 82.

Expansion of the middle area causes a reduction in data area. When themiddle area is extended, time for filling an unrecorded data area withthe terminators in finalization can be shortened, and finalizing timecan be shortened.

In the embodiment, the middle area can be extended even after thepadding of the guard track zone of the middle area of layer 0 in stepS12. The step of extending the middle area is executed immediatelybefore step S16 (padding of guard track zone of middle area of layer 1)or step S18 (recording of data in data area of layer 1) in FIG. 76.

The present invention is not directly limited to the above embodiments.In an execution phase, the present invention can be embodied bymodifying the constituent elements without departing from the spirit andscope of the invention. Various inventions can be formed byappropriately combining a plurality of constituent elements disclosed inthe above embodiments. For example, several constituent elements may beomitted from all the constituent elements disclosed in the embodiments.Furthermore, the constituent elements used over the differentembodiments may be appropriately combined to each other. For example, astructure in which two recording layers are used as shown in FIG. 1A maybe applied to a pigment-based recording film as shown in FIG. 1B. Morespecifically, the present invention may be applied to a single-sidedmultilayer DH_DVD-R disc in which two or more pigment-based recordingfilms are laminated.

While certain embodiments of the inventions have been described, theseembodiments have been presented by way of example only, and are notintended to limit the scope of the inventions. Indeed, the novel methodsand systems described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the methods and systems described herein may be made withoutdeparting from the spirit of the inventions. The accompanying claims andtheir equivalents are intended to cover such forms or modifications aswould fall within the scope and spirit of the inventions.

1. An information storage medium comprising: a burst cutting area; asystem lead-in area located outward of the burst cutting area; and adata area located outward of the system lead-in area, wherein the burstcutting area is configured to store information indicative of a versionnumber; and the system lead-in area is configured to store informationindicative of the version number.
 2. A method for reproducinginformation from an information storage medium comprising: a burstcutting area; a system lead-in area located outward of the burst cuttingarea; and a data area located outward of the system lead-in area, thedata area storing data information, wherein the burst cutting area isconfigured to store information indicative of a version number, and thesystem lead-in area is configured to store information indicative of theversion number, the method comprising: irradiating the informationstorage medium with light; and reproducing the data information from theinformation storage medium.
 3. An apparatus for reproducing informationfrom an information storage medium comprising: a burst cutting area; asystem lead-in area located outward of the burst cutting area; and adata area located outward of the system lead-in area, the data areastoring data information, wherein the burst cutting area is configuredto store information indicative of a version number, and the systemlead-in area is configured to store information indicative of theversion number, the apparatus comprising: an optical head configured toirradiate the information storage medium with light; and a reproducingmodule configured to reproduce the data information from the informationstorage medium.
 4. A method for recording information on an informationstorage medium comprising: a burst cutting area; a system lead-in arealocated outward of the burst cutting area; and a data area locatedoutward of the system lead-in area, wherein the burst cutting area isconfigured to store information indicative of a version number, and thesystem lead-in area is configured to store information indicative of theversion number, the method comprising: irradiating the informationstorage medium with light; and recording information on the informationstorage medium.
 5. An apparatus for recording information on aninformation storage medium comprising: a burst cutting area; a systemlead-in area located outward of the burst cutting area; and a data arealocated outward of the system lead-in area, wherein the burst cuttingarea is configured to store information indicative of a version number,and the system lead-in area is configured to store informationindicative of the version number, the apparatus comprising: an opticalhead configured to irradiate the information storage medium with light;and a recording module configured to record information on theinformation storage medium.